1
|
Tedesco JCG, Jandre V, Carvalho AMG, Kockelmann W, Többens DM, Cardoso LP, Coelho AA, Bordallo HN. Simulating selected magnetic properties of Tb xPr 1-xAl 2, a magnetocaloric compound. J Phys Condens Matter 2024; 36:145802. [PMID: 38157558 DOI: 10.1088/1361-648x/ad19a2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2023] [Accepted: 12/28/2023] [Indexed: 01/03/2024]
Abstract
TbxPr1-xAl2are ferrimagnetic materials exhibiting magnetocaloric effect that have gained considerable attention due to their potential use as an alternative in refrigeration, magnetic sensors and in information storage technology. Here using the mean field approach numerical simulations were conducted forx= 0.1, 0.2, 0.3, 0.4, 0.5, and 0.75, to analyze selected physical properties, such as x-ray and neutron powder diffraction, magnetization and heat capacity. The simulations successfully reproduced the experimental data providing a comprehensive characterization and improved understanding of this family of compound.
Collapse
Affiliation(s)
- Julio C G Tedesco
- Polytechnic Institute of the State University of Rio de Janeiro-UERJ, 28625-570, Rua Bonfim 25, Vila Amélia, Nova Friburgo, RJ, Brazil
- Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
- Institute of Physics 'Gleb Wataghin', Estate University of Campinas-UNICAMP, 13083- 859 Campinas, SP, Brazil
| | - Vagner Jandre
- Polytechnic Institute of the State University of Rio de Janeiro-UERJ, 28625-570, Rua Bonfim 25, Vila Amélia, Nova Friburgo, RJ, Brazil
| | - Alexandre Magnus G Carvalho
- Chemical Engineering Department, São Paulo Federal University, 09913-030 Diadema, SP, Brazil
- Mechanical Engineering Department, Maringá State University, 87020-900 Maringaé, PR, Brazil
- Institute of Physics Armando Dias Tavares, State University of Rio de Janeiro-UERJ, 20550-013, Rua São Francisco Xavier, 524, Rio de Janeiro, RJ, Brazil
| | - Winfried Kockelmann
- Science and Technology Facilities Council (STFC), Rutherford Appleton Laboratory, ISIS Facility, Harwell OX11 0Qx, United Kingdom
| | - Daniel M Többens
- Helmholtz-Zentrum Berlin für Materialien und Energie GmbH (HZB), Hahn-Meitner-Platz 1, 14109 Berlin, Germany
| | - Lisandro P Cardoso
- Institute of Physics 'Gleb Wataghin', Estate University of Campinas-UNICAMP, 13083- 859 Campinas, SP, Brazil
| | - Adelino A Coelho
- Institute of Physics 'Gleb Wataghin', Estate University of Campinas-UNICAMP, 13083- 859 Campinas, SP, Brazil
| | - Heloisa N Bordallo
- Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
| |
Collapse
|
2
|
Halloran T, Desrochers F, Zhang EZ, Chen T, Chern LE, Xu Z, Winn B, Graves-Brook M, Stone MB, Kolesnikov AI, Qiu Y, Zhong R, Cava R, Kim YB, Broholm C. Geometrical frustration versus Kitaev interactions in BaCo(2)(AsO(4))(2). Proc Natl Acad Sci U S A 2023; 120:e2215509119. [PMID: 36608295 DOI: 10.1073/pnas.2215509119] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Recently, Co-based honeycomb magnets have been proposed as promising candidate materials to host the Kitaev spin liquid (KSL) state. One of the front-runners is BaCo2(AsO4)2 (BCAO), where it was suggested that the exchange processes between Co2+ ions via the surrounding edge-sharing oxygen octahedra could give rise to bond-dependent Kitaev interactions. In this work, we present and analyze a comprehensive inelastic neutron scattering (INS) study of BCAO with fields in the honeycomb plane. Combining the constraints from the magnon excitations in the high-field polarized state and the inelastic spin structure factor measured in zero magnetic field, we examine two leading theoretical models: the Kitaev-type [Formula: see text] model and the XXZ[Formula: see text]model. We show that the existing experimental data can be consistently accounted for by the XXZ[Formula: see text]model but not by the [Formula: see text] model, and we discuss the implications of these results for the realization of a spin liquid phase in BCAO and more generally for the realization of the Kitaev model in cobaltates.
Collapse
|
3
|
Gerlits O, Fajer M, Cheng X, Blumenthal DK, Radić Z, Kovalevsky A. Structural and dynamic effects of paraoxon binding to human acetylcholinesterase by X-ray crystallography and inelastic neutron scattering. Structure 2022; 30:1538-1549.e3. [PMID: 36265484 PMCID: PMC9637784 DOI: 10.1016/j.str.2022.09.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Revised: 09/07/2022] [Accepted: 09/25/2022] [Indexed: 11/06/2022]
Abstract
Organophosphorus (OP) compounds, including nerve agents and some pesticides, covalently bind to the catalytic serine of human acetylcholinesterase (hAChE), thereby inhibiting acetylcholine hydrolysis necessary for efficient neurotransmission. Oxime antidotes can reactivate the OP-conjugated hAChE, but reactivation efficiency can be low for pesticides, such as paraoxon (POX). Understanding structural and dynamic determinants of OP inhibition and reactivation can provide insights to design improved reactivators. Here, X-ray structures of hAChE with unaged POX, with POX and oximes MMB4 and RS170B, and with MMB4 are reported. A significant conformational distortion of the acyl loop was observed upon POX binding, being partially restored to the native conformation by oximes. Neutron vibrational spectroscopy combined with molecular dynamics simulations showed that picosecond vibrational dynamics of the acyl loop soften in the ∼20-50 cm-1 frequency range. The acyl loop structural perturbations may be correlated with its picosecond vibrational dynamics to yield more comprehensive template for structure-based reactivator design.
Collapse
Affiliation(s)
- Oksana Gerlits
- Department of Natural Sciences, Tennessee Wesleyan University, Athens, TN 37303, USA
| | - Mikolai Fajer
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Xiaolin Cheng
- Division of Medicinal Chemistry & Pharmacognosy, College of Pharmacy, The Ohio State University, Columbus, OH 43210, USA
| | - Donald K Blumenthal
- Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, UT 84112, USA
| | - Zoran Radić
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA 92093-0657, USA.
| | - Andrey Kovalevsky
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.
| |
Collapse
|
4
|
Xie T, Liu C, Kajimoto R, Ikeuchi K, Li S, Luo H. Spin fluctuations in the 112-type iron-based superconductor Ca 0.82La 0.18Fe 0.96Ni 0.04As 2. J Phys Condens Matter 2022; 34:474001. [PMID: 36137515 DOI: 10.1088/1361-648x/ac9441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Accepted: 09/22/2022] [Indexed: 06/16/2023]
Abstract
We report time-of-flight inelastic neutron scattering (INS) investigations on the spin fluctuation spectrum in the 112-type iron-based superconductor (FeSC) Ca0.82La0.18Fe0.96Ni0.04As2(CaLa-112). In comparison to the 122-type FeSCs with a centrosymmetric tetragonal lattice structure (space groupI4/mmm) at room temperature and an in-plane stripe-type antiferromagnetic (AF) order at low temperature, the 112 system has a noncentrosymmetric structure (space groupP21) with additional zigzag arsenic chains between Ca/La layers and a magnetic ground state with similar wavevectorQAFbut different orientations of ordered moments in the parent compounds. Our INS study clearly reveals that the in-plane dispersions and the bandwidth of spin excitations in the superconducting CaLa-112 closely resemble to those in 122 systems. While the total fluctuating moments⟨m2⟩≈4.6±0.2μB2/Fe are larger than 122 system, the dynamic correlation lengths are similar (ξ ≈ 10 Å). These results suggest that superconductivity in iron arsenides may have a common magnetic origin under similar magnetic exchange couplings with a dual nature from local moments and itinerant electrons, despite their different magnetic patterns and lattice symmetries.
Collapse
Affiliation(s)
- Tao Xie
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, United States of America
| | - Chang Liu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, People's Republic of China
| | - Ryoichi Kajimoto
- Materials and Life Science Division, J-PARC Center, Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195, Japan
| | - Kazuhiko Ikeuchi
- Neutron Science and Technology Center, Comprehensive Research Organization for Science and Society, Tokai, Ibaraki 319-1106, Japan
| | - Shiliang Li
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, People's Republic of China
| | - Huiqian Luo
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, People's Republic of China
| |
Collapse
|
5
|
Suepaul S, Forrest KA, Georgiev PA, Forster PM, Lohstroh W, Grzimek V, Dunning SG, Reynolds JE, Humphrey SM, Eckert J, Space B, Pham T. Investigating H 2 Adsorption in Isostructural Metal-Organic Frameworks M-CUK-1 (M = Co and Mg) through Experimental and Theoretical Studies. ACS Appl Mater Interfaces 2022; 14:8126-8136. [PMID: 35119825 DOI: 10.1021/acsami.1c20312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
A combined experimental and theoretical study of H2 adsorption was carried out in Co-CUK-1 and Mg-CUK-1, two isostructural metal-organic frameworks (MOFs) that consist of M2+ ions (M = Co and Mg) coordinated to pyridine-2,4-dicarboxylate (pdc2-) and OH- ligands. These MOFs possess saturated metal centers in distorted octahedral environments and narrow pore sizes and display high chemical and thermal stability. Previous experimental studies revealed that Co-CUK-1 exhibits a H2 uptake of 183 cm3 g-1 at 77 K/1.0 atm [ Angew. Chem., Int. Ed. 2007, 46, 272-275, DOI: 10.1002/anie.200601627], while that for Mg-CUK-1 under the same conditions is 240 cm3 g-1 on the basis of the experimental measurements carried out herein. The theoretical H2 adsorption isotherms are in close agreement with the corresponding experimental measurements for simulations using electrostatic and polarizable potentials of the adsorbate. Through simulated annealing calculations, it was found that the primary binding site for H2 in both isostructural analogues is localized proximal to the center of the aromatic rings belonging to the pdc2- linkers. Inelastic neutron scattering (INS) spectroscopic studies of H2 adsorbed in both MOFs revealed a rotational tunnelling transition occurring at around 8 meV in the corresponding spectra; this peak represents H2 adsorbed at the primary binding site. Two-dimensional quantum rotation calculations for H2 localized at the primary and secondary binding sites in both MOFs yielded rotational energy levels that are in agreement with the transitions observed in the INS spectra. Even though both M-CUK-1 analogues possess different metal ions, they exhibit similar electrostatic environments, modeled structures at H2 saturation, and rotational potentials for H2 adsorbed at the most favorable adsorption site. Overall, this study demonstrates how important molecular-level details of the H2 adsorption mechanism inside MOF micropores can be derived from a combination of experimental measurements and theoretical calculations using two stable and isostructural MOFs with saturated metal centers and small pore windows as model systems.
Collapse
Affiliation(s)
- Shanelle Suepaul
- Department of Chemistry, University of South Florida, 4202 East Fowler Avenue, CHE205, Tampa, Florida 33620-5250, United States
| | - Katherine A Forrest
- Department of Chemistry, University of South Florida, 4202 East Fowler Avenue, CHE205, Tampa, Florida 33620-5250, United States
| | - Peter A Georgiev
- Department for Solid State Physics and Microelectronics, Faculty of Physics, University of Sofia, 5 James Bourchier Boulevard, Sofia 1164, Bulgaria
| | - Paul M Forster
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, Nevada 89154, United States
| | - Wiebke Lohstroh
- Heinz Maier-Leibnitz Zentrum (MLZ), Technische Universität München, Lichtenbergstraße 1, D-85748 Garching, Germany
| | - Veronika Grzimek
- Helmholtz-Zentrum Berlin, für Materialien und Energie, Lise-Meitner Campus, Hahn-Meitner-Platz 1, 14109 Berlin, Germany
| | - Samuel G Dunning
- Department of Chemistry, The University of Texas at Austin, Welch Hall 4.428, 105 East 24th Street, Stop A5300, Austin, Texas 78712-1224, United States
| | - Joseph E Reynolds
- Department of Chemistry, The University of Texas at Austin, Welch Hall 4.428, 105 East 24th Street, Stop A5300, Austin, Texas 78712-1224, United States
| | - Simon M Humphrey
- Department of Chemistry, The University of Texas at Austin, Welch Hall 4.428, 105 East 24th Street, Stop A5300, Austin, Texas 78712-1224, United States
| | - Juergen Eckert
- Department of Chemistry, University of South Florida, 4202 East Fowler Avenue, CHE205, Tampa, Florida 33620-5250, United States
- Department of Chemistry and Biochemistry, Texas Tech University, 2500 Broadway, Box 41 061, Lubbock, Texas 79409-1061, United States
| | - Brian Space
- Department of Chemistry, University of South Florida, 4202 East Fowler Avenue, CHE205, Tampa, Florida 33620-5250, United States
- Department of Chemistry, North Carolina State University, 2700 Stinson Drive, Cox Hall 506, Raleigh, North Carolina 27607, United States
| | - Tony Pham
- Department of Chemistry, University of South Florida, 4202 East Fowler Avenue, CHE205, Tampa, Florida 33620-5250, United States
| |
Collapse
|
6
|
Nolasco MM, Ribeiro-Claro PJA, Vaz PD. Vibrational Dynamics in crystalline 4-(dimethylamino) benzaldehyde: Inelastic Neutron Scattering and Periodic DFT Study. Materials (Basel) 2022; 15:475. [PMID: 35057193 DOI: 10.3390/ma15020475] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Revised: 01/05/2022] [Accepted: 01/05/2022] [Indexed: 01/04/2023]
Abstract
The structure and dynamics of crystalline 4-(dimethylamino) benzaldehyde, 4DMAB, are assessed through INS spectroscopy combined with periodic DFT calculations. The excellent agreement between experimental and calculated spectra is the basis for a reliable assignment of INS bands. The external phonon modes of crystalline 4DMAB are quite well described by the simulated spectrum, as well as the modes involving low-frequency molecular vibrations. Crystal field splitting is predicted and observed for the modes assigned to the dimethylamino group. Concerning the torsional motion of methyl groups, four individual bands are identified and assigned to specific methyl groups in the asymmetric unit. The torsional frequencies of the four methyl groups in the asymmetric unit fall in a region of ca. 190 ± 20 cm-1, close to the range of values observed for methyl groups bonding to unsaturated carbon atoms. The hybridization state of the X atom in X-CH3 seems to play a key role in determining the methyl torsional frequency.
Collapse
|
7
|
Mamontov E, Daemen LL, Novak E, Stone MB. Melting and Re-Freezing Leads to Irreversible Changes in the Morphology and Molecular-Level Dynamics of Pfizer-BioNTech COVID-19 Vaccine. Medicina (Kaunas) 2021; 57:1343. [PMID: 34946288 DOI: 10.3390/medicina57121343] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Revised: 12/01/2021] [Accepted: 12/06/2021] [Indexed: 12/01/2022]
Abstract
Background and Objectives: As an mRNA-based vaccine, the Pfizer-BioNTech COVID-19 vaccine has stringent cold storage requirements to preserve functionality of the mRNA active ingredient. To this end, lipid components of the vaccine formulation play an important role in stabilizing and protecting the mRNA molecule for long-term storage. The purpose of the current study was to measure molecular-level dynamics as a function of temperature in the Pfizer-BioNTech COVID-19 vaccine to gain microscopic insight into its thermal stability. Materials and Methods: We used quasielastic and inelastic neutron scattering to probe (1) the vaccine extracted from the manufacturer-supplied vials and (2) unperturbed vaccine in the original manufacturer-supplied vials. The latter measurement was possible due to the high penetrative power of neutrons. Results: Upon warming from the low-temperature frozen state, the vaccine in its original form exhibits two-step melting, indicative of a two-phase morphology. Once the melting is completed (above 0 °C), vaccine re-freezing cannot restore its original two-phase state. This observation is corroborated by the changes in the molecular vibrational spectra. The molecular-level mobility measured in the resulting single-phase state of the re-frozen vaccine greatly exceeds the mobility measured in the original vaccine. Conclusions: Even a brief melting (above 0 °C) leads to an irreversible alteration of the two-phase morphology of the original vaccine formulation. Re-freezing of the vaccine results in a one-phase morphology with much increased molecular-level mobility compared to that in the original vaccine, suggesting irreversible deterioration of the vaccine’s in-storage stability. Neutron scattering can be used to distinguish between the vibrational spectra characteristic of the original and deteriorated vaccines contained in the unperturbed original manufacturer-supplied vials.
Collapse
|
8
|
Ribeiro-Claro PJA, Vaz PD, Nolasco MM, Gil FPSC, de Carvalho LAEB, Marques MPM, Amado AM. New Insights on the Vibrational Dynamics of 2-Methoxy-, 4-Methoxy- and 4-Ethoxy-Benzaldehyde from INS Spectra and Periodic DFT Calculations. Materials (Basel) 2021; 14:4561. [PMID: 34443083 DOI: 10.3390/ma14164561] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 07/29/2021] [Accepted: 08/05/2021] [Indexed: 12/01/2022]
Abstract
The dynamics of 2-methoxybenzaldehyde, 4-methoxybenzaldehyde, and 4-ethoxybenzaldehyde in the solid state are assessed through INS spectroscopy combined with periodic DFT calculations. In the absence of experimental data for 4-ethoxybenzaldehyde, a tentative crystal structure, based on its similarity with 4-methoxybenzaldehyde, is considered and evaluated. The excellent agreement between calculated and experimental spectra allows a confident assignment of the vibrational modes. Several spectral features in the INS spectra are unambiguously assigned and torsional potential barriers for the methyl groups are derived from experimental frequencies. The intramolecular nature of the potential energy barrier for methyl rotation about O–CH3 bonds compares with the one reported for torsion about saturated C–CH3 bonds. On the other hand, the intermolecular contribution to the potential energy barrier may represent 1/3 of the barrier height in these systems.
Collapse
|
9
|
Hester G, DeLazzer TN, Yahne DR, Sarkis CL, Zhao HD, Rivera JAR, Calder S, Ross KA. Magnetic properties of the Ising-like rare earth pyrosilicate: D-Er 2Si 2O 7. J Phys Condens Matter 2021; 33:405801. [PMID: 34252896 DOI: 10.1088/1361-648x/ac136a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 07/12/2021] [Indexed: 06/13/2023]
Abstract
Ising-like spin-1/2 magnetic materials are of interest for their ready connection to theory, particularly in the context of quantum critical behavior. In this work we report detailed studies of the magnetic properties of a member of the rare earth pyrosilicate family, D-Er2Si2O7, which is known to display a highly anisotropic Ising-likeg-tensor and effective spin-1/2 magnetic moments. We used powder neutron diffraction, powder inelastic neutron spectroscopy (INS), and single crystal AC susceptibility to characterize its magnetic properties. Neutron diffraction enabled us to determine the magnetic structure below the known transition temperature (TN= 1.9 K) in zero field, confirming that the magnetic state is a four-sublattice antiferromagnetic structure with two non-collinear Ising axes, as was previously hypothesized. Our powder INS data revealed a gapped excitation at zero field, consistent with anisotropic (possibly Ising) exchange. An applied field of 1 T produces a mode softening, which is consistent with a field-induced second order phase transition. To assess the relevance of D-Er2Si2O7to the transverse field Ising model, we performed AC susceptibility measurements on a single crystal with the magnetic field oriented in the direction transverse to the Ising axes. This revealed a transition at 2.65 T at 0.1 K, a field significantly higher than the mode-softening field observed by powder INS, showing that the field-induced phase transitions are highly field-direction dependent as expected. These measurements suggest that D-Er2Si2O7may be a candidate for further exploration related to the transverse field Ising model.
Collapse
Affiliation(s)
- Gavin Hester
- Department of Physics, Colorado State University, 200 W. Lake St., Fort Collins, CO 80523-1875, United States of America
| | - T N DeLazzer
- Department of Physics, Colorado State University, 200 W. Lake St., Fort Collins, CO 80523-1875, United States of America
| | - D R Yahne
- Department of Physics, Colorado State University, 200 W. Lake St., Fort Collins, CO 80523-1875, United States of America
| | - C L Sarkis
- Department of Physics, Colorado State University, 200 W. Lake St., Fort Collins, CO 80523-1875, United States of America
| | - H D Zhao
- Department of Physics, University of Colorado-Boulder, Boulder, CO 80309, United States of America
| | - J A Rodriguez Rivera
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899-6102, United States of America
- Department of Materials Science and Engineering, University of Maryland, College Park, MD 20740, United States of America
| | - S Calder
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, United States of America
| | - K A Ross
- Department of Physics, Colorado State University, 200 W. Lake St., Fort Collins, CO 80523-1875, United States of America
- Quantum Materials Program, CIFAR, Toronto, Ontario M5G 1Z8, Canada
| |
Collapse
|
10
|
Balacescu L, Brandl G, Radulescu A. Separation of the inelastic and elastic scattering in time-of-flight mode on the pinhole small-angle neutron scattering diffractometer K-WS-2. J Appl Crystallogr 2021; 54:1217-1224. [PMID: 34429724 PMCID: PMC8366428 DOI: 10.1107/s1600576721006610] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Accepted: 06/24/2021] [Indexed: 02/19/2023] Open
Abstract
To study and control the incoherent inelastic background in small-angle neutron scattering, which makes a significant contribution to the detected scattering from hydrocarbon systems, the KWS-2 small-angle neutron scattering diffractometer operated by the Jülich Centre for Neutron Science (JCNS) at Heinz-Maier Leibnitz Zentrum (MLZ), Garching, Germany, was equipped with a secondary single-disc chopper that is placed in front of the sample stage. This makes it possible to record in time-of-flight mode the scattered neutrons in the high-Q regime of the instrument (i.e. short incoming wavelengths and detection distances) and to discard the inelastic component from the measured data. Examples of measurements on different materials routinely used as standard samples, sample containers and solvents in the experiments at KWS-2 are presented. When only the elastic region of the spectrum is used in the data-reduction procedure, a decrease of up to two times in the incoherent background of the experimentally measured scattering cross section may be obtained. The proof of principle is demonstrated on a solution of bovine serum albumin in D2O.
Collapse
Affiliation(s)
- Livia Balacescu
- Jülich Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum (MLZ), Forschungszentrum Jülich GmbH, Lichtenbergstrasse 1, Garching, 85747, Germany
- Physikalisches Institut (IA), Rheinisch-Westfälische Technische Hochschule (RWTH), Otto-Blumenthal Strasse, Aachen, 52074, Germany
| | - Georg Brandl
- Jülich Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum (MLZ), Forschungszentrum Jülich GmbH, Lichtenbergstrasse 1, Garching, 85747, Germany
| | - Aurel Radulescu
- Jülich Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum (MLZ), Forschungszentrum Jülich GmbH, Lichtenbergstrasse 1, Garching, 85747, Germany
| |
Collapse
|
11
|
Podlesnyak A, Nikitin SE, Ehlers G. Low-energy spin dynamics in rare-earth perovskite oxides. J Phys Condens Matter 2021; 33:403001. [PMID: 34252895 DOI: 10.1088/1361-648x/ac1367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Accepted: 07/12/2021] [Indexed: 06/13/2023]
Abstract
We review recent studies of spin dynamics in rare-earth orthorhombic perovskite oxides of the type RMO3, where R is a rare-earth ion and M is a transition-metal ion, using single-crystal inelastic neutron scattering (INS). After a short introduction to the magnetic INS technique in general, the results of INS experiments on both transition-metal and rare-earth subsystems for four selected compounds (YbFeO3, TmFeO3, YFeO3, YbAlO3) are presented. We show that the spectrum of magnetic excitations consists of two types of collective modes that are well separated in energy: gapped magnons with a typical bandwidth of <70 meV, associated with the antiferromagnetically (AFM) ordered transition-metal subsystem, and AFM fluctuations of <5 meV within the rare-earth subsystem, with no hybridization of those modes. We discuss the high-energy conventional magnon excitations of the 3dsubsystem only briefly, and focus in more detail on the spectacular dynamics of the rare-earth sublattice in these materials. We observe that the nature of the ground state and the low-energy excitation strongly depends on the identity of the rare-earth ion. In the case of non-Kramers ions, the low-symmetry crystal field completely eliminates the degeneracy of the multiplet state, creating a rich magnetic field-temperature phase diagram. In the case of Kramers ions, the resulting ground state is at least a doublet, which can be viewed as an effective quantum spin-1/2. Equally important is the fact that in Yb-based materials the nearest-neighbor exchange interaction dominates in one direction, despite the three-dimensional nature of the orthoperovskite crystal structure. The observation of a fractional spinon continuum and quantum criticality in YbAlO3demonstrates that Kramers rare-earth based magnets can provide realizations of various aspects of quantum low-dimensional physics.
Collapse
Affiliation(s)
- A Podlesnyak
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, United States of America
| | - S E Nikitin
- Paul Scherrer Institute, CH-5232 Villigen, Switzerland
| | - G Ehlers
- Neutron Technologies Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, United States of America
| |
Collapse
|
12
|
Senesi R, Andreani C, Baglioni P, Batista de Carvalho LAE, Licoccia S, Marques MPM, Moretti G, Noce A, Paolesse R, Parker SF, Preziosi E, Romanelli G, Romani A, Di Daniele N. Looking for Minor Phenolic Compounds in Extra Virgin Olive Oils Using Neutron and Raman Spectroscopies. Antioxidants (Basel) 2021; 10:antiox10050643. [PMID: 33922163 PMCID: PMC8145310 DOI: 10.3390/antiox10050643] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 04/16/2021] [Accepted: 04/19/2021] [Indexed: 12/11/2022] Open
Abstract
Extra virgin olive oil (EVOO) is defined as a functional food as it contains numerous phenolic components with well-recognized health-beneficial properties, such as high antioxidant and anti-inflammatory capacity. These characteristics depend on their structural/conformational behavior, which is largely determined by intra- and intermolecular H-bond interactions. While the vibrational dynamics of isolated compounds have been studied in a number of recent investigations, their signal in a real-life sample of EVOO is overwhelmed by the major constituent acids. Here, we provide a full characterization of the vibrational spectroscopic signal from commercially available EVOO samples using Inelastic Neutron Scattering (INS) and Raman spectroscopies. The spectra are dominated by CH2 vibrations, especially at about 750 cm−1 and 1300 cm−1. By comparison with the spectra from hydroxytyrosol and other minor phenolic compounds, we show that the best regions in which to look for the structure–activity information related to the minor polar compounds is at 675 and 1200 cm−1 for hydroxytyrosol, and around 450 cm−1 for all minor polar compounds used as reference, especially if a selectively deuterated sample is available. The regional origin of the EVOO samples investigated appears to be related to the different amount of phenolic esters versus acids as reflected by the relative intensities of the peaks at 1655 and 1747 cm−1.
Collapse
Affiliation(s)
- Roberto Senesi
- NAST Centre, Physics Department, Università degli Studi di Roma “Tor Vergata”, Via della Ricerca, Scientifica 1, 00133 Rome, Italy; (R.S.); (C.A.); (E.P.)
- CNR-IPCF Sezione di Messina, Viale Ferdinando Stagno d’Alcontres 37, 98158 Messina, Italy
| | - Carla Andreani
- NAST Centre, Physics Department, Università degli Studi di Roma “Tor Vergata”, Via della Ricerca, Scientifica 1, 00133 Rome, Italy; (R.S.); (C.A.); (E.P.)
| | - Piero Baglioni
- CSGI and Chemistry Department, University of Florence, Via della Lastruccia 3, Sesto Fiorentino, 50019 Florence, Italy; (P.B.); (G.M.)
| | | | - Silvia Licoccia
- NAST Centre, Chemical Science and Technologies Department, Università degli Studi di Roma “Tor Vergata”, Via della Ricerca Scientifica 1, 00133 Rome, Italy; (S.L.); (R.P.)
| | - Maria P. M. Marques
- Molecular Physical-Chemistry R&D Unit, Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal;
- Department of Life Sciences, University of Coimbra, 3000-456 Coimbra, Portugal
- Correspondence: (M.P.M.M.); (G.R.)
| | - Giulia Moretti
- CSGI and Chemistry Department, University of Florence, Via della Lastruccia 3, Sesto Fiorentino, 50019 Florence, Italy; (P.B.); (G.M.)
| | - Annalisa Noce
- UOC of Internal Medicine-Center of Hypertension, Nephrology Unit, Department of Systems Medicine, Università degli Studi di Roma “Tor Vergata”, Via Montpellier 1, 00133 Rome, Italy; (A.N.); (N.D.D.)
| | - Roberto Paolesse
- NAST Centre, Chemical Science and Technologies Department, Università degli Studi di Roma “Tor Vergata”, Via della Ricerca Scientifica 1, 00133 Rome, Italy; (S.L.); (R.P.)
| | - Stewart F. Parker
- ISIS Facility, STFC Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 0QX, UK;
| | - Enrico Preziosi
- NAST Centre, Physics Department, Università degli Studi di Roma “Tor Vergata”, Via della Ricerca, Scientifica 1, 00133 Rome, Italy; (R.S.); (C.A.); (E.P.)
| | - Giovanni Romanelli
- ISIS Facility, STFC Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 0QX, UK;
- Correspondence: (M.P.M.M.); (G.R.)
| | - Annalisa Romani
- PHYTOLAB (Pharmaceutical, Cosmetic, Food Supplement, Technology and Analysis)-DiSIA, University of Florence, Via U. Schiff, 6, 50019 Sesto Fiorentino, Italy;
| | - Nicola Di Daniele
- UOC of Internal Medicine-Center of Hypertension, Nephrology Unit, Department of Systems Medicine, Università degli Studi di Roma “Tor Vergata”, Via Montpellier 1, 00133 Rome, Italy; (A.N.); (N.D.D.)
| |
Collapse
|
13
|
Dally RL, Phelan D, Bishop N, Ghimire NJ, Lynn JW. Isotropic Nature of the Metallic Kagome Ferromagnet Fe 3Sn 2 at High Temperatures. Crystals (Basel) 2021; 11:10.3390/cryst11030307. [PMID: 38487672 PMCID: PMC10938373 DOI: 10.3390/cryst11030307] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Anisotropy and competing exchange interactions have emerged as two central ingredients needed for centrosymmetric materials to exhibit topological spin textures. Fe3Sn2 is thought to have these ingredients as well, as it has recently been discovered to host room temperature skyrmionic bubbles with an accompanying topological Hall effect. We present small-angle inelastic neutron scattering measurements that unambiguously show that Fe3Sn2 is an isotropic ferromagnet below T C ≈ 660 K to at least 480 K - the lower temperature threshold of our experimental configuration. Fe3Sn2 is known to have competing magnetic exchange interactions, correlated electron behavior, weak magnetocrystalline anisotropy, and lattice anisotropy; all of these features are thought to play a role in stabilizing skyrmions in centrosymmetric systems. Our results reveal that at elevated temperatures, there is an absence of magnetocrystalline anisotropy and that the system behaves as a typical exchange ferromagnet with a spin stiffness D T = 0 K = 271 ± 9 meV Å 2 .
Collapse
Affiliation(s)
- Rebecca L. Dally
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899-6102
| | - Daniel Phelan
- Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439
| | - Nicholas Bishop
- Department of Physics and Astronomy, George Mason University, Fairfax, VA 22030
| | - Nirmal J. Ghimire
- Department of Physics and Astronomy, George Mason University, Fairfax, VA 22030
- Quantum Science and Engineering Center, George Mason University, Fairfax, VA 22030
| | - Jeffrey W. Lynn
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899-6102
| |
Collapse
|
14
|
Bartkowiak M, Prokeš K, Fromme M, Budack A, Dirlick J, Prokhnenko O. EXEQ and InEXEQ: software tools for experiment planning at the Extreme Environment Diffractometer. J Appl Crystallogr 2020; 53:1613-1619. [PMID: 33304227 PMCID: PMC7710490 DOI: 10.1107/s1600576720011942] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Accepted: 08/30/2020] [Indexed: 05/30/2023] Open
Abstract
EXEQ/InEXEQ software is a dedicated tool for single-crystal orientation at the HFM-EXED neutron scattering facility, and also a mandatory step of the proposal submission process. The Extreme Environment Diffractometer was a neutron time-of-flight instrument equipped with a constant-field hybrid magnet providing magnetic fields up to 26 T. The magnet infrastructure and sample environment imposed limitations on the geometry of the experiment, making it necessary to plan the experiment with care. EXEQ is the software tool developed to allow users of the instrument to find the optimal sample orientation for their diffraction experiment. InEXEQ fulfilled the same role for the inelastic neutron scattering experiments. The source code of the software is licensed under the GNU General Public Licence 3, allowing it to be used by other facilities and adapted for use on other instruments.
Collapse
Affiliation(s)
- Maciej Bartkowiak
- Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Lise Meitner Campus, Hahn-Meitner-Platz 1, 14109 Berlin, Germany
| | - Karel Prokeš
- Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Lise Meitner Campus, Hahn-Meitner-Platz 1, 14109 Berlin, Germany
| | - Michael Fromme
- Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Lise Meitner Campus, Hahn-Meitner-Platz 1, 14109 Berlin, Germany
| | - Anne Budack
- Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Lise Meitner Campus, Hahn-Meitner-Platz 1, 14109 Berlin, Germany
| | - Juliane Dirlick
- Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Lise Meitner Campus, Hahn-Meitner-Platz 1, 14109 Berlin, Germany
| | - Oleksandr Prokhnenko
- Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Lise Meitner Campus, Hahn-Meitner-Platz 1, 14109 Berlin, Germany
| |
Collapse
|
15
|
Colognesi D, Demmel F, Filabozzi A, Pietropaolo A, Pozio A, Romanelli G, Santucci A, Tosti S. Proton Dynamics in Palladium-Silver: An Inelastic Neutron Scattering Investigation. Molecules 2020; 25:molecules25235587. [PMID: 33261164 PMCID: PMC7730539 DOI: 10.3390/molecules25235587] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Revised: 11/23/2020] [Accepted: 11/24/2020] [Indexed: 11/29/2022] Open
Abstract
Proton dynamics in Pd77Ag23 membranes is investigated by means of various neutron spectroscopic techniques, namely Quasi Elastic Neutron Scattering, Incoherent Inelastic Neutron Scattering, Neutron Transmission, and Deep Inelastic Neutron Scattering. Measurements carried out at the ISIS spallation neutron source using OSIRIS, MARI and VESUVIO spectrometers were performed at pressures of 1, 2, and 4 bar, and temperatures in the 330–673 K range. The energy interval spanned by the different instruments provides information on the proton dynamics in a time scale ranging from about 102 to 10−4 ps. The main finding is that the macroscopic diffusion process is determined by microscopic jump diffusion. In addition, the vibrational density of states of the H atoms in the metal lattice has been determined for a number of H concentrations and temperatures. These measurements follow a series of neutron diffraction experiments performed on the same sample and thus provide a complementary information for a thorough description of structural and dynamical properties of H-loaded Pd-Ag membranes.
Collapse
Affiliation(s)
- Daniele Colognesi
- Consiglio Nazionale delle Ricerche, Istituto di Fisica Applicata “N. Carrara”, via Madonna del Piano 10, 50019 Sesto Fiorentino, Italy;
| | - Franz Demmel
- Science and Technology Facilities Council, ISIS Facility, Harwell Oxford, Oxfordshire OX11 0QX, UK; (F.D.); (G.R.)
| | - Alessandra Filabozzi
- Università degli Studi di Roma “Tor Vergata”, Dipartimento di Fisica, Via della Ricerca Scientifica 1, 00133 Rome, Italy;
| | - Antonino Pietropaolo
- ENEA, Dipartimento di Fusione e Tecnologie per la Sicurezza Nucleare, via E. Fermi 45, 00044 Frascati, Italy; (A.S.); (S.T.)
- Correspondence:
| | - Alfonso Pozio
- ENEA, Dipartimento Tecnologie Energetiche, Via Anguillarese 301, 00123 S. Maria di Galeria (Rome), Italy;
| | - Giovanni Romanelli
- Science and Technology Facilities Council, ISIS Facility, Harwell Oxford, Oxfordshire OX11 0QX, UK; (F.D.); (G.R.)
| | - Alessia Santucci
- ENEA, Dipartimento di Fusione e Tecnologie per la Sicurezza Nucleare, via E. Fermi 45, 00044 Frascati, Italy; (A.S.); (S.T.)
| | - Silvano Tosti
- ENEA, Dipartimento di Fusione e Tecnologie per la Sicurezza Nucleare, via E. Fermi 45, 00044 Frascati, Italy; (A.S.); (S.T.)
| |
Collapse
|
16
|
De Francesco A, Scaccia L, Formisano F, Guarini E, Bafile U, Maccarini M, Alatas A, Cai YQ, Cunsolo A. The Terahertz Dynamics of an Aqueous Nanoparticle Suspension: An Inelastic X-ray Scattering Study. Nanomaterials (Basel) 2020; 10:nano10050860. [PMID: 32365679 PMCID: PMC7711609 DOI: 10.3390/nano10050860] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Revised: 04/23/2020] [Accepted: 04/24/2020] [Indexed: 11/16/2022]
Abstract
We used the high-resolution Inelastic X-ray Scattering beamline of the Advanced Photon Source at Argonne National Laboratory to measure the terahertz spectrum of pure water and a dilute aqueous suspension of 15 nm diameter spherical Au nanoparticles (Au-NPs). We observe that, despite their sparse volume concentration of about 0.5%, the immersed NPs strongly influence the collective molecular dynamics of the hosting liquid. We investigate this effect through a Bayesian inference analysis of the spectral lineshape, which elucidates how terahertz transport properties of water change upon Au-NP immersion. In particular, we observe a nearly complete disappearance of the longitudinal acoustic mode and a mildly decreased ability to support shear wave propagation.
Collapse
Affiliation(s)
- Alessio De Francesco
- Consiglio Nazionale delle Ricerche, Istituto Officina dei Materiali, Operative Group in Grenoble (OGG), F-38042 Grenoble, France; (A.D.F.); (F.F.)
- Institut Laue-Langevin (ILL), F-38042 Grenoble, France
| | - Luisa Scaccia
- Dipartimento di Economia e Diritto, Università di Macerata, Via Crescimbeni 20, 62100 Macerata, Italy;
| | - Ferdinando Formisano
- Consiglio Nazionale delle Ricerche, Istituto Officina dei Materiali, Operative Group in Grenoble (OGG), F-38042 Grenoble, France; (A.D.F.); (F.F.)
- Institut Laue-Langevin (ILL), F-38042 Grenoble, France
| | - Eleonora Guarini
- Dipartimento di Fisica e Astronomia, Università di Firenze, via G. Sansone 1, I-50019 Sesto Fiorentino, Italy;
| | - Ubaldo Bafile
- Consiglio Nazionale delle Ricerche, Istituto di Fisica Applicata ”Nello Carrara”, via Madonna del Piano 10, I-50019 Sesto Fiorentino, Italy;
| | - Marco Maccarini
- Université Grenoble-Alpes - Laboratoire TIMC/IMAG UMR CNRS 5525, 38000 Grenoble, France;
| | - Ahmet Alatas
- Argonne National Laboratory, Advanced Photon Source, P.O. Box 5000 Upton, 11973 NY, USA;
| | - Yong Q. Cai
- Brookhaven National Laboratory-National Synchrotron Light Source-NSLS II, P.O. Box 5000, Upton, 11973 NY, USA;
| | - Alessandro Cunsolo
- Brookhaven National Laboratory-National Synchrotron Light Source-NSLS II, P.O. Box 5000, Upton, 11973 NY, USA;
- Correspondence: ; Tel.: +1-631-327-1927
| |
Collapse
|
17
|
Adilina IB, Aulia F, Fitriady MA, Oemry F, Widjaya RR, Parker SF. Computational and Spectroscopic Studies of Carbon Disulfide. Molecules 2020; 25:E1901. [PMID: 32326027 DOI: 10.3390/molecules25081901] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2020] [Revised: 04/14/2020] [Accepted: 04/15/2020] [Indexed: 11/22/2022] Open
Abstract
The vibrational spectroscopy of CS2 has been investigated many times in all three phases. However, there is still some ambiguity about the location of two of the modes in the solid state. The aim of this work was to locate all of the modes by inelastic neutron scattering (INS) spectroscopy, (which has no selection rules), and to use periodic density functional theory to provide a complete and unambiguous assignment of all the modes in the solid state. A comparison of the observed and calculated INS spectra shows generally good agreement. All four of the ν2 bending mode components are calculated to fall within 14 cm−1. Inspection of the spectrum shows that there are no bands close to the intense feature at 390 cm−1 (assigned to ν2); this very strongly indicates that the Au mode is within the envelope of the 390 cm−1 band. Based on a simulation of the band shape of the 390 cm−1 feature, the most likely position of the optically forbidden component of the ν2 bending mode is 393 ± 2 cm−1. The calculations show that the optically inactive Au translational mode is strongly dispersed, so it does not result in a single feature in the INS spectrum.
Collapse
|
18
|
Vilela C, Freire CSR, Araújo C, Rudić S, Silvestre AJD, Vaz PD, Ribeiro-Claro PJA, Nolasco MM. Understanding the Structure and Dynamics of Nanocellulose-Based Composites with Neutral and ionic Poly(methacrylate) Derivatives using Inelastic Neutron Scattering and DFT Calculations. Molecules 2020; 25:molecules25071689. [PMID: 32272703 PMCID: PMC7180936 DOI: 10.3390/molecules25071689] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Revised: 04/02/2020] [Accepted: 04/04/2020] [Indexed: 02/05/2023]
Abstract
Bacterial nanocellulose (BC)-based composites containing poly(2-hydroxyethyl methacrylate) (PHEMA), poly(methacroylcholine chloride) (PMACC) or poly(methacroylcholine hydroxide) (PMACH) were characterized by inelastic neutron scattering (INS) spectroscopy, combined with DFT (density functional theory) calculations of model systems. A reasonable match between calculated and experimental spectral lines and their intensities was used to support the vibrational assignment of the observed bands and to validate the possible structures. The differences between the spectra of the nanocomposites and the pure precursors indicate that interactions between the components are stronger for the ionic poly(methacrylate) derivatives than for the neutral counterpart. Displaced anions interact differently with cellulose chains, due to the different ability to compete with the O-H···O hydrogen bonds in cellulose. Hence, the INS is an adequate technique to delve deeper into the structure and dynamics of nanocellulose-based composites, confirming that they are true nanocomposite materials instead of simple mixtures of totally independent domains.
Collapse
Affiliation(s)
- Carla Vilela
- CICECO—Aveiro Institute of Materials, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal; (C.S.R.F.); (C.A.); (A.J.D.S.); (P.J.A.R.-C.)
- Correspondence: (C.V.); (M.M.N.)
| | - Carmen S. R. Freire
- CICECO—Aveiro Institute of Materials, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal; (C.S.R.F.); (C.A.); (A.J.D.S.); (P.J.A.R.-C.)
| | - Catarina Araújo
- CICECO—Aveiro Institute of Materials, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal; (C.S.R.F.); (C.A.); (A.J.D.S.); (P.J.A.R.-C.)
| | - Svemir Rudić
- ISIS Neutron & Muon Source, Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 0QX, UK;
| | - Armando J. D. Silvestre
- CICECO—Aveiro Institute of Materials, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal; (C.S.R.F.); (C.A.); (A.J.D.S.); (P.J.A.R.-C.)
| | - Pedro D. Vaz
- Champalimaud Foundation, Champalimaud Centre for the Unknown, Lisbon, 1400-038 Lisboa, Portugal;
| | - Paulo J. A. Ribeiro-Claro
- CICECO—Aveiro Institute of Materials, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal; (C.S.R.F.); (C.A.); (A.J.D.S.); (P.J.A.R.-C.)
| | - Mariela M. Nolasco
- CICECO—Aveiro Institute of Materials, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal; (C.S.R.F.); (C.A.); (A.J.D.S.); (P.J.A.R.-C.)
- Correspondence: (C.V.); (M.M.N.)
| |
Collapse
|
19
|
Nolasco MM, Araujo CF, Vaz PD, Amado AM, Ribeiro-Claro P. Vibrational Dynamics of Crystalline 4-Phenylbenzaldehyde from INS Spectra and Periodic DFT Calculations. Molecules 2020; 25:E1374. [PMID: 32197316 PMCID: PMC7144378 DOI: 10.3390/molecules25061374] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Revised: 03/14/2020] [Accepted: 03/16/2020] [Indexed: 01/05/2023] Open
Abstract
The present work emphasizes the value of periodic density functional theory (DFT) calculations in the assessment of the vibrational spectra of molecular crystals. Periodic calculations provide a nearly one-to-one match between the calculated and observed bands in the inelastic neutron scattering (INS) spectrum of crystalline 4-phenylbenzaldehyde, thus validating their assignment and correcting previous reports based on single molecule calculations. The calculations allow the unambiguous assignment of the phenyl torsional mode at ca. 118-128 cm-1, from which a phenyl torsional barrier of ca. 4000 cm-1 is derived, and the identification of the collective mode involving the antitranslational motion of CH···O bonded pairs, a hallmark vibrational mode of systems where C-H···O contacts are an important feature.
Collapse
Affiliation(s)
- Mariela M Nolasco
- CICECO, Departamento de Química, Universidade de Aveiro, P-3810-193 Aveiro, Portugal
| | - Catarina F Araujo
- CICECO, Departamento de Química, Universidade de Aveiro, P-3810-193 Aveiro, Portugal
| | - Pedro D Vaz
- Champalimaud Foundation, Champalimaud Centre for the Unknown, 1400-038 Lisboa, Portugal
| | - Ana M Amado
- Química-Física Molecular, Departamento de Química, FCTUC, Universidade de Coimbra, P-3004-535 Coimbra, Portugal
| | - Paulo Ribeiro-Claro
- CICECO, Departamento de Química, Universidade de Aveiro, P-3810-193 Aveiro, Portugal
| |
Collapse
|
20
|
Parker SF, Cavaye H, Callear SK. Structure and Dynamics of the Superprotonic Conductor Caesium Hydrogen Sulfate, CsHSO 4. Molecules 2020; 25:molecules25061271. [PMID: 32168860 PMCID: PMC7143950 DOI: 10.3390/molecules25061271] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Revised: 03/06/2020] [Accepted: 03/07/2020] [Indexed: 12/03/2022] Open
Abstract
We have investigated caesium hydrogen sulfate, CsHSO4, in all three of its ambient pressure phases by total scattering neutron diffraction, inelastic neutron scattering (INS) and Raman spectroscopies and periodic density functional theory calculations. Above 140 °C, CsHSO4 undergoes a phase transition to a superprotonic conductor that has potential application in intermediate temperature fuel cells. Total scattering neutron diffraction data clearly show that all the existing structures of this phase are unable to describe the local structure, because they have either partial occupancies of the atoms and/or non-physical O–H distances. Knowledge of the local structure is crucial because it is this that determines the conduction mechanism. Starting from one of the previous models, we have generated a new structure that has no partial occupancies and reasonable O–H distances. After geometry optimisation, the calculated radial distribution function is in reasonable agreement with the experimental data, as are the calculated and observed INS and Raman spectra. This work is particularly notable in that we have measured INS spectra in the O–H stretch region above room temperature, which is extremely rare. The INS spectra have the enormous advantage that the electrical anharmonicity that complicates the infrared spectra is absent and the stretch modes are plainly seen.
Collapse
|
21
|
Borgschulte A, Terreni J, Billeter E, Daemen L, Cheng Y, Pandey A, Łodziana Z, Hemley RJ, Ramirez-Cuesta AJ. Inelastic neutron scattering evidence for anomalous H-H distances in metal hydrides. Proc Natl Acad Sci U S A 2020; 117:4021-6. [PMID: 32029594 DOI: 10.1073/pnas.1912900117] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Hydrogen-containing materials are of fundamental as well as technological interest. An outstanding question for both is the amount of hydrogen that can be incorporated in such materials, because that determines dramatically their physical properties such as electronic and crystalline structure. The number of hydrogen atoms in a metal is controlled by the interaction of hydrogens with the metal and by the hydrogen-hydrogen interactions. It is well established that the minimal possible hydrogen-hydrogen distances in conventional metal hydrides are around 2.1 Å under ambient conditions, although closer H-H distances are possible for materials under high pressure. We present inelastic neutron scattering measurements on hydrogen in [Formula: see text] showing nonexpected scattering at low-energy transfer. The analysis of the spectra reveals that these spectral features in part originate from hydrogen vibrations confined by neighboring hydrogen at distances as short as 1.6 Å. These distances are much smaller than those found in related hydrides, thereby violating the so-called Switendick criterion. The results have implications for the design and creation of hydrides with additional properties and applications.
Collapse
|
22
|
Chen SH, Corsaro C, Mallamace F, Fazio E, Mallamace D. The Proton Density of States in Confined Water (H 2O). Int J Mol Sci 2019; 20:E5373. [PMID: 31671726 DOI: 10.3390/ijms20215373] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Revised: 10/17/2019] [Accepted: 10/24/2019] [Indexed: 12/05/2022] Open
Abstract
The hydrogen density of states (DOS) in confined water has been probed by inelastic neutron scattering spectra in a wide range of its P–T phase diagram. The liquid–liquid transition and the dynamical crossover from the fragile (super-Arrhenius) to strong (Arrhenius) glass forming behavior have been studied, by taking into account the system polymorphism in both the liquid and amorphous solid phases. The interest is focused in the low energy region of the DOS (E<10 meV) and the data are discussed in terms of the energy landscape (local minima of the potential energy) approach. In this latest research, we consider a unit scale energy (EC) linked to the water local order governed by the hydrogen bonding (HB). All the measured spectra, scaled according to such energy, evidence a universal power law behavior with different exponents (γ) in the strong and fragile glass forming regions, respectively. In the first case, the DOS data obey the Debye squared-frequency law, whereas, in the second one, we obtain a value predicted in terms of the mode-coupling theory (MCT) (γ≃1.6).
Collapse
|
23
|
De Francesco A, Scaccia L, Maccarini M, Formisano F, Guarini E, Bafile U, Cunsolo A. Interpreting the Terahertz Spectrum of Complex Materials: The Unique Contribution of the Bayesian Analysis. Materials (Basel) 2019; 12:E2914. [PMID: 31505798 PMCID: PMC6766264 DOI: 10.3390/ma12182914] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 08/19/2019] [Accepted: 08/29/2019] [Indexed: 11/16/2022]
Abstract
In the last few decades, experimental studies of the terahertz spectrum of density fluctuations have considerably improved our knowledge of the mesoscopic dynamics of disordered materials, which also have imposed new demands on the data modelling and interpretation. Indeed, lineshape analyses are no longer limited to the phenomenological observation of inelastic features, as in the pioneering stage of Neutron or X-ray spectroscopy, rather aiming at the extraction from their shape of physically relevant quantities, as sound velocity and damping, relaxation times, or other transport coefficients. In this effort, researchers need to face both inherent and practical obstacles, respectively stemming from the highly damped nature of terahertz modes and the limited energy resolution, accessible kinematic region and statistical accuracy of the typical experimental outcome. To properly address these challenges, a global reconsideration of the lineshape modelling and the enforcement of evidence-based probabilistic inference is becoming crucial. Particularly compelling is the possibility of implementing Bayesian inference methods, which we illustrated here through an in-depth discussion of some results recently obtained in the analysis of Neutron and X-ray scattering results.
Collapse
Affiliation(s)
- Alessio De Francesco
- Consiglio Nazionale delle Ricerche, Istituto Officina dei Materiali, Operative Group in Grenoble (OGG), c/o Institut Laue Langevin, 38042 Grenoble, France
| | - Luisa Scaccia
- Dipartimento di Economia e Diritto, Università di Macerata, Via Crescimbeni 20, 62100 Macerata, Italy
| | - Marco Maccarini
- Laboratoire TIMC/IMAG UMR CNRS 5525 Grenoble, Université Grenoble-Alpes, 38000 Grenoble, France
| | - Ferdinando Formisano
- Consiglio Nazionale delle Ricerche, Istituto Officina dei Materiali, Operative Group in Grenoble (OGG), c/o Institut Laue Langevin, 38042 Grenoble, France
| | - Eleonora Guarini
- Dipartimento di Fisica e Astronomia, Università di Firenze, via G. Sansone 1, I-50019 Sesto Fiorentino, Italy
| | - Ubaldo Bafile
- Consiglio Nazionale delle Ricerche, Istituto di Fisica Applicata "Nello Carrara", via Madonna del Piano 10, I-50019 Sesto Fiorentino, Italy
| | - Alessandro Cunsolo
- Brookhaven National Laboratory-National Synchrotron Light Source-NSLS II, P.O. Box 5000, Upton, NY 11973, USA.
| |
Collapse
|
24
|
Sato T, Daemen LL, Cheng Y, Ramirez-Cuesta AJ, Ikeda K, Aoki T, Otomo T, Orimo SI. Hydrogen-Release Reaction of a Complex Transition Metal Hydride with Covalently Bound Hydrogen and Hydride Ions. Chemphyschem 2019; 20:1392-1397. [PMID: 30575253 DOI: 10.1002/cphc.201801082] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2018] [Revised: 12/18/2018] [Indexed: 11/09/2022]
Abstract
The hydrogen-release reaction of a complex transition metal hydride, LaMg2 NiH7 , composed of La3+ , 2×Mg2+ , [NiH4 ]4- and 3×H- , was studied by thermal analyses, powder X-ray, and neutron diffraction and inelastic neutron scattering. Upon heating, LaMg2 NiH7 released hydrogen at approximately 567 K and decomposed into LaH2-3 and Mg2 Ni. Before the reaction, covalently bound hydrogen (Hc °v. ) in [NiH4 ]4- exhibited a larger atomic displacement than H- , although a weakening of the chemical bonds around [NiH4 ]4- and H- was observed. These results indicate the precursor phenomenon of a hydrogen-release reaction, wherein there is a large atomic displacement of Hc °v. that induces the hydrogen-release reaction rather than H- . As an isothermal reaction, LaMg2 NiH7 formed LaMg2 NiH2.4 at 503 K in vacuum for 48 h, and LaMg2 NiH2.4 reacted with hydrogen to reform LaMg2 NiH7 at 473 K under 1 MPa of H2 gas pressure for 10 h. These results revealed that LaMg2 NiH7 exhibited partially reversible hydrogen-release and uptake reactions.
Collapse
Affiliation(s)
- Toyoto Sato
- Institute for Materials Research, Tohoku University, Sendai, Miyagi, 980-8577, Japan
| | - Luke L Daemen
- Neutron Scattering Division, Spallation Neutron Source, Oak Ridge National Laboratory, Oak Ridge, Tennessee, 37831, USA
| | - Yongqiang Cheng
- Neutron Scattering Division, Spallation Neutron Source, Oak Ridge National Laboratory, Oak Ridge, Tennessee, 37831, USA
| | - Anibal J Ramirez-Cuesta
- Neutron Scattering Division, Spallation Neutron Source, Oak Ridge National Laboratory, Oak Ridge, Tennessee, 37831, USA
| | - Kazutaka Ikeda
- Institute of Materials Structure Science, High Energy Accelerator Research Organization, Tsukuba, Ibaraki, 305-0801, Japan
| | - Takuma Aoki
- Institute for Materials Research, Tohoku University, Sendai, Miyagi, 980-8577, Japan
| | - Toshiya Otomo
- Institute of Materials Structure Science, High Energy Accelerator Research Organization, Tsukuba, Ibaraki, 305-0801, Japan
| | - Shin-Ichi Orimo
- Institute for Materials Research, Tohoku University, Sendai, Miyagi, 980-8577, Japan.,WPI-Advanced Institute for Materials Research (AIMR), Tohoku University, Sendai, Miyagi, 980-8577, Japan
| |
Collapse
|
25
|
Singh B, Gupta MK, Mittal R, Zbiri M, Hodgson SA, Goodwin AL, Schober H, Chaplot SL. Anomalous Lattice Dynamics in AgC 4N 3: Insights From Inelastic Neutron Scattering and Density Functional Calculations. Front Chem 2018; 6:544. [PMID: 30483494 PMCID: PMC6240580 DOI: 10.3389/fchem.2018.00544] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Accepted: 10/19/2018] [Indexed: 11/13/2022] Open
Abstract
We have performed temperature dependent inelastic neutron scattering measurements to study the anharmonicity of phonon spectra of AgC4N3. The analysis and interpretation of the experimental spectra is done using ab-initio lattice dynamics calculations. The calculated phonon spectrum over the entire Brillouin zone is used to derive linear thermal expansion coefficients. The effect of van der Waals interaction on structure stability has been investigated using advanced density functional methods. The calculated isothermal equation of states implies a negative linear compressibility along the c-axis of the crystal, which also leads to a negative thermal expansion along this direction. The role of elastic properties inducing the observed anomalous lattice behavior is discussed.
Collapse
Affiliation(s)
- Baltej Singh
- Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai, India
- Homi Bhabha National Institute, Mumbai, India
| | - Mayanak K. Gupta
- Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai, India
| | - Ranjan Mittal
- Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai, India
- Homi Bhabha National Institute, Mumbai, India
| | | | - Sarah A. Hodgson
- Department of Chemistry, University of Oxford, Oxford, United Kingdom
| | - Andrew L. Goodwin
- Department of Chemistry, University of Oxford, Oxford, United Kingdom
| | | | - Samrath L. Chaplot
- Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai, India
- Homi Bhabha National Institute, Mumbai, India
| |
Collapse
|
26
|
Kim DS, Hellman O, Herriman J, Smith HL, Lin JYY, Shulumba N, Niedziela JL, Li CW, Abernathy DL, Fultz B. Nuclear quantum effect with pure anharmonicity and the anomalous thermal expansion of silicon. Proc Natl Acad Sci U S A 2018; 115:1992-1997. [PMID: 29440490 PMCID: PMC5834665 DOI: 10.1073/pnas.1707745115] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Despite the widespread use of silicon in modern technology, its peculiar thermal expansion is not well understood. Adapting harmonic phonons to the specific volume at temperature, the quasiharmonic approximation, has become accepted for simulating the thermal expansion, but has given ambiguous interpretations for microscopic mechanisms. To test atomistic mechanisms, we performed inelastic neutron scattering experiments from 100 K to 1,500 K on a single crystal of silicon to measure the changes in phonon frequencies. Our state-of-the-art ab initio calculations, which fully account for phonon anharmonicity and nuclear quantum effects, reproduced the measured shifts of individual phonons with temperature, whereas quasiharmonic shifts were mostly of the wrong sign. Surprisingly, the accepted quasiharmonic model was found to predict the thermal expansion owing to a large cancellation of contributions from individual phonons.
Collapse
Affiliation(s)
- D S Kim
- Department of Applied Physics and Materials Science, California Institute of Technology, Pasadena, CA 91125;
| | - O Hellman
- Department of Applied Physics and Materials Science, California Institute of Technology, Pasadena, CA 91125
| | - J Herriman
- Department of Applied Physics and Materials Science, California Institute of Technology, Pasadena, CA 91125
| | - H L Smith
- Department of Applied Physics and Materials Science, California Institute of Technology, Pasadena, CA 91125
| | - J Y Y Lin
- Neutron Data Analysis and Visualization Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831
| | - N Shulumba
- Department of Mechanical and Civil Engineering, California Institute of Technology, Pasadena, CA 91125
| | - J L Niedziela
- Instrument and Source Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831
| | - C W Li
- Department of Mechanical Engineering, University of California, Riverside, CA 92521
| | - D L Abernathy
- Quantum Condensed Matter Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831
| | - B Fultz
- Department of Applied Physics and Materials Science, California Institute of Technology, Pasadena, CA 91125;
| |
Collapse
|
27
|
Woolfson RJ, Timco GA, Chiesa A, Vitorica-Yrezabal IJ, Tuna F, Guidi T, Pavarini E, Santini P, Carretta S, Winpenny REP. [CrF(O2 C(t) Bu)2 ]9 : Synthesis and Characterization of a Regular Homometallic Ring with an Odd Number of Metal Centers and Electrons. Angew Chem Int Ed Engl 2016; 55:8856-9. [PMID: 27294807 PMCID: PMC5089673 DOI: 10.1002/anie.201601734] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Revised: 03/30/2016] [Indexed: 11/24/2022]
Abstract
The first regular homometallic ring containing an odd number of metal centers is reported. The ring was synthesized by means of amine-templated self-assembly. Extensive physical characterization studies, including magnetic measurements, powder inelastic neutron scattering (INS), and DFT calculations, show that the molecule has a near perfect match to the expected behavior for a frustrated system with the lowest energy pair of S=1/2 spin states separated by only 0.1 meV (0.8 cm(-1) ).
Collapse
Affiliation(s)
- Robert J Woolfson
- School of Chemistry and Photon Science Institute, University of Manchester, Oxford Road, Manchester, M20 4NZ, UK
| | - Grigore A Timco
- School of Chemistry and Photon Science Institute, University of Manchester, Oxford Road, Manchester, M20 4NZ, UK
| | - Alessandro Chiesa
- Dipartimento di Fisica e Scienze della Terra, Università di Parma, Parco Area della Scienze 7/A, I-43124, Parma, Italy
| | - Inigo J Vitorica-Yrezabal
- School of Chemistry and Photon Science Institute, University of Manchester, Oxford Road, Manchester, M20 4NZ, UK
| | - Floriana Tuna
- School of Chemistry and Photon Science Institute, University of Manchester, Oxford Road, Manchester, M20 4NZ, UK
| | - Tatiana Guidi
- ISIS Facility, Rutherford Appleton Laboratory, Didcot, OX11 0QX, UK
| | - Eva Pavarini
- Institute for Advanced Simulation, Forschungzentrum Jülich, 52425, Jülich, Germany
- JARA High Performance Computing, RWTH Aachen University, 52062, Aachen, Germany
| | - Paolo Santini
- Dipartimento di Fisica e Scienze della Terra, Università di Parma, Parco Area della Scienze 7/A, I-43124, Parma, Italy
| | - Stefano Carretta
- Dipartimento di Fisica e Scienze della Terra, Università di Parma, Parco Area della Scienze 7/A, I-43124, Parma, Italy
| | - Richard E P Winpenny
- School of Chemistry and Photon Science Institute, University of Manchester, Oxford Road, Manchester, M20 4NZ, UK.
| |
Collapse
|
28
|
Baker ML, Lancaster T, Chiesa A, Amoretti G, Baker PJ, Barker C, Blundell SJ, Carretta S, Collison D, Güdel HU, Guidi T, McInnes EJL, Möller JS, Mutka H, Ollivier J, Pratt FL, Santini P, Tuna F, Tregenna-Piggott PLW, Vitorica-Yrezabal IJ, Timco GA, Winpenny REP. Studies of a Large Odd-Numbered Odd-Electron Metal Ring: Inelastic Neutron Scattering and Muon Spin Relaxation Spectroscopy of Cr8 Mn. Chemistry 2016; 22:1779-88. [PMID: 26748964 PMCID: PMC4744977 DOI: 10.1002/chem.201503431] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Indexed: 11/05/2022]
Abstract
The spin dynamics of Cr8Mn, a nine‐membered antiferromagnetic (AF) molecular nanomagnet, are investigated. Cr8Mn is a rare example of a large odd‐membered AF ring, and has an odd‐number of 3d‐electrons present. Odd‐membered AF rings are unusual and of interest due to the presence of competing exchange interactions that result in frustrated‐spin ground states. The chemical synthesis and structures of two Cr8Mn variants that differ only in their crystal packing are reported. Evidence of spin frustration is investigated by inelastic neutron scattering (INS) and muon spin relaxation spectroscopy (μSR). From INS studies we accurately determine an appropriate microscopic spin Hamiltonian and we show that μSR is sensitive to the ground‐spin‐state crossing from S=1/2 to S=3/2 in Cr8Mn. The estimated width of the muon asymmetry resonance is consistent with the presence of an avoided crossing. The investigation of the internal spin structure of the ground state, through the analysis of spin‐pair correlations and scalar‐spin chirality, shows a non‐collinear spin structure that fluctuates between non‐planar states of opposite chiralities.
Collapse
Affiliation(s)
- Michael L Baker
- School of Chemistry and Photon Science Institute, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK. .,Institut Laue-Langevin, BP 156, 6 rue Jules Horowitz, 38042, Grenoble Cedex 9, France.
| | - Tom Lancaster
- Department of Physics, Durham University, South Road, Durham, DH1 3LE, UK
| | - Alessandro Chiesa
- Dipartimento di Fisica e Scienze della Terra, Università di Parma, 43124, Parma, Italy
| | - Giuseppe Amoretti
- Dipartimento di Fisica e Scienze della Terra, Università di Parma, 43124, Parma, Italy
| | - Peter J Baker
- ISIS Facility, Rutherford Appleton Laboratory, Didcot, OX11 0QX, UK
| | - Claire Barker
- School of Chemistry and Photon Science Institute, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK
| | - Stephen J Blundell
- Clarendon Laboratory, Department of Physics, University of Oxford, OX1 3PU, UK.
| | - Stefano Carretta
- Dipartimento di Fisica e Scienze della Terra, Università di Parma, 43124, Parma, Italy
| | - David Collison
- School of Chemistry and Photon Science Institute, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK
| | - Hans U Güdel
- Department of Chemistry and Biochemistry, University of Bern, 3000, Bern, Switzerland
| | - Tatiana Guidi
- ISIS Facility, Rutherford Appleton Laboratory, Didcot, OX11 0QX, UK
| | - Eric J L McInnes
- School of Chemistry and Photon Science Institute, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK
| | - Johannes S Möller
- Clarendon Laboratory, Department of Physics, University of Oxford, OX1 3PU, UK
| | - Hannu Mutka
- Institut Laue-Langevin, BP 156, 6 rue Jules Horowitz, 38042, Grenoble Cedex 9, France
| | - Jacques Ollivier
- Institut Laue-Langevin, BP 156, 6 rue Jules Horowitz, 38042, Grenoble Cedex 9, France
| | - Francis L Pratt
- ISIS Facility, Rutherford Appleton Laboratory, Didcot, OX11 0QX, UK
| | - Paolo Santini
- Dipartimento di Fisica e Scienze della Terra, Università di Parma, 43124, Parma, Italy
| | - Floriana Tuna
- School of Chemistry and Photon Science Institute, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK
| | | | - Iñigo J Vitorica-Yrezabal
- School of Chemistry and Photon Science Institute, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK
| | - Grigore A Timco
- School of Chemistry and Photon Science Institute, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK
| | - Richard E P Winpenny
- School of Chemistry and Photon Science Institute, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK.
| |
Collapse
|
29
|
Abstract
The single-particle dynamics of hydrogen atoms in several of the amorphous ices are reported using a combination of deep inelastic neutron scattering (DINS) and inelastic neutron scattering (INS). The mean kinetic energies of the hydrogen nuclei are found to increase with increasing density, indicating the weakening of hydrogen bonds as well as a trend toward steeper and more harmonic hydrogen vibrational potential energy surfaces. DINS shows much more pronounced changes in the O-H stretching component of the mean kinetic energy going from low- to high-density amorphous ices than indicated by INS and Raman spectroscopy. This highlights the power of the DINS technique to retrieve accurate ground-state kinetic energies beyond the harmonic approximation. In a novel approach, we use information from DINS and INS to determine the anharmonicity constants of the O-H stretching modes. Furthermore, our experimental kinetic energies will serve as important benchmark values for path-integral Monte Carlo simulations.
Collapse
Affiliation(s)
- A Parmentier
- †Dipartimento di Fisica and NAST Centre, Università degli Studi di Roma Tor Vergata, Via della Ricerca Scientifica 1, 00133 Roma, Italy
| | - J J Shephard
- ‡Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom
- §Department of Chemistry, Durham University, South Road, Durham DH1 3LE, United Kingdom
| | - G Romanelli
- †Dipartimento di Fisica and NAST Centre, Università degli Studi di Roma Tor Vergata, Via della Ricerca Scientifica 1, 00133 Roma, Italy
| | - R Senesi
- †Dipartimento di Fisica and NAST Centre, Università degli Studi di Roma Tor Vergata, Via della Ricerca Scientifica 1, 00133 Roma, Italy
- ∥CNR-IPCF Sezione di Messina, Viale F. Stagno D'Alcontres 37, 98158 Messina, Italy
| | - C G Salzmann
- ‡Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom
| | - C Andreani
- †Dipartimento di Fisica and NAST Centre, Università degli Studi di Roma Tor Vergata, Via della Ricerca Scientifica 1, 00133 Roma, Italy
- ∥CNR-IPCF Sezione di Messina, Viale F. Stagno D'Alcontres 37, 98158 Messina, Italy
| |
Collapse
|
30
|
Xu M, Ye S, Lawler R, Turro NJ, Bačić Z. HD in C₆₀: theoretical prediction of the inelastic neutron scattering spectrum and its temperature dependence. Philos Trans A Math Phys Eng Sci 2013; 371:20110630. [PMID: 23918712 DOI: 10.1098/rsta.2011.0630] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
We report rigorous quantum calculations of the inelastic neutron scattering (INS) spectra of HD@C₆₀, over a range of temperatures from 0 to 240 K and for two incident neutron wavelengths used in recent experimental investigations. The computations were performed using our newly developed methodology, which incorporates the coupled five-dimensional translation-rotation (T-R) eigenstates of the guest molecule as the initial and final states of the INS transitions, and yields highly detailed spectra. Depending on the incident neutron wavelength, the number of computed INS transitions varies from almost 500 to over 2000. The low-temperature INS spectra display the fingerprints of the coupling between the translational and rotational motions of the entrapped HD molecule, which is responsible for the characteristic splitting patterns of the T-R energy levels. INS transitions from the ground T-R state of HD to certain sublevels of excited T-R multiplets have zero intensity and are absent from the spectra. This surprising finding is explained by the new INS selection rule introduced here. The calculated spectra exhibit strong temperature dependence. As the temperature increases, numerous new peaks appear, arising from the transitions originating in excited T-R states which become populated. Our calculations show that the higher temperature features typically comprise two or more transitions close in energy and with similar intensities, interspersed with numerous other transitions whose intensities are negligible. This implies that accurately calculated energies and intensities of INS transitions which our methodology provides will be indispensable for reliable interpretation and assignment of the experimental spectra of HD@C₆₀ and related systems at higher temperatures.
Collapse
Affiliation(s)
- Minzhong Xu
- Department of Chemistry, New York University, New York, NY 10003, USA
| | | | | | | | | |
Collapse
|
31
|
Horsewill AJ, Goh K, Rols S, Ollivier J, Johnson MR, Levitt MH, Carravetta M, Mamone S, Murata Y, Chen JYC, Johnson JA, Lei X, Turro NJ. Quantum rotation and translation of hydrogen molecules encapsulated inside C₆₀: temperature dependence of inelastic neutron scattering spectra. Philos Trans A Math Phys Eng Sci 2013; 371:20110627. [PMID: 23918709 DOI: 10.1098/rsta.2011.0627] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The quantum dynamics of a hydrogen molecule encapsulated inside the cage of a C60 fullerene molecule is investigated using inelastic neutron scattering (INS). The emphasis is on the temperature dependence of the INS spectra which were recorded using time-of-flight spectrometers. The hydrogen endofullerene system is highly quantum mechanical, exhibiting both translational and rotational quantization. The profound influence of the Pauli exclusion principle is revealed through nuclear spin isomerism. INS is shown to be exceptionally able to drive transitions between ortho-hydrogen and para-hydrogen which are spin-forbidden to photon spectroscopies. Spectra in the temperature range 1.6≤T≤280 K are presented, and examples are given which demonstrate how the temperature dependence of the INS peak amplitudes can provide an effective tool for assigning the transitions. It is also shown in a preliminary investigation how the temperature dependence may conceivably be used to probe crystal field effects and inter-fullerene interactions.
Collapse
Affiliation(s)
- A J Horsewill
- School of Physics and Astronomy, University of Nottingham, , Nottingham NG7 2RD, UK.
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
32
|
Teixeira SCM, Ankner J, Bellissent-Funel MC, Bewley R, Blakeley MP, Coates L, Dahint R, Dalgliesh R, Dencher N, Dhont J, Fischer P, Forsyth VT, Fragneto G, Frick B, Geue T, Gilles R, Gutberlet T, Haertlein M, Hauß T, Häußler W, Heller WT, Herwig K, Holderer O, Juranyi F, Kampmann R, Knott R, Kohlbrecher J, Kreuger S, Langan P, Lechner R, Lynn G, Majkrzak C, May R, Meilleur F, Mo Y, Mortensen K, Myles DAA, Natali F, Neylon C, Niimura N, Ollivier J, Ostermann A, Peters J, Pieper J, Rühm A, Schwahn D, Shibata K, Soper AK, Straessle T, Suzuki UI, Tanaka I, Tehei M, Timmins P, Torikai N, Unruh T, Urban V, Vavrin R, Weiss K, Zaccai G. New sources and instrumentation for neutrons in biology. Chem Phys 2009; 345:133-151. [PMID: 19132140 PMCID: PMC2614686 DOI: 10.1016/j.chemphys.2008.02.030] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Neutron radiation offers significant advantages for the study of biological molecular structure and dynamics. A broad and significant effort towards instrumental and methodological development to facilitate biology experiments at neutron sources worldwide is reviewed.
Collapse
Affiliation(s)
- S C M Teixeira
- Institut Laue Langevin, 6 rue Jules Horowitz, 38042 Grenoble cedex 9, France
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
33
|
Garrett PE, Warr N, Yates SW. Nuclear Structure Studies With the Inelastic Neutron Scattering Reaction and Gamma-Ray Detection. J Res Natl Inst Stand Technol 2000; 105:141-5. [PMID: 27551599 PMCID: PMC4878344 DOI: 10.6028/jres.105.019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 07/22/1999] [Indexed: 05/26/2023]
Abstract
The (n,n'γ) reaction has been used at the University of Kentucky accelerator facility to examine the detailed structure of a number of nuclei. The advantages of this method are reviewed, and recent developments are described. Examples of unique nuclear structure studies that have been carried out with this method are presented.
Collapse
Affiliation(s)
- P E Garrett
- Lawrence Livermore National Laboratory Livermore, CA 94551
| | - N Warr
- University of Kentucky Lexington, KY 40506-0055
| | - S W Yates
- University of Kentucky Lexington, KY 40506-0055
| |
Collapse
|
34
|
Trevino SF. The Triple Axis and SPINS Spectrometers. J Res Natl Inst Stand Technol 1993; 98:59-69. [PMID: 28053458 PMCID: PMC4927249 DOI: 10.6028/jres.098.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
In this paper are described the triple axis and spin polarized inelastic neutron scattering (SPINS) spectrometers which are installed at the NIST Cold Neutron Research Facility (CNRF). The general principle of operation of these two instruments is described in sufficient detail to allow the reader to make an informed decision as to their usefulness for his needs. However, it is the intention of the staff at the CNRF to provide the expert resources for their efficient use in any given situation. Thus, this work is not intended as a user manual but rather as a guide into the range of applicability of the two instruments.
Collapse
|
35
|
Neumann DA, Hammouda B. Ultra-High Resolution Inelastic Neutron Scattering. J Res Natl Inst Stand Technol 1993; 98:89-108. [PMID: 28053460 PMCID: PMC4927251 DOI: 10.6028/jres.098.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Two types of ultra high energy resolution neutron scattering instruments, the backscattering spectrometer and the spin echo spectrometer, are described. Examples of the types of research which can be done with these instruments are given and plans for a cold neutron backscattering spectrometer which will be built in the NIST Cold Neutron Research Facility (CNRF) are discussed. It is hoped that this information will be of use to researchers considering neutron scattering experiments at NIST.
Collapse
Affiliation(s)
- D A Neumann
- National Institute of Standards and Technology, Gaithersburg, MD 20899
| | - B Hammouda
- National Institute of Standards and Technology, Gaithersburg, MD 20899
| |
Collapse
|