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Zhang H, Datchi F, Andriambariarijaona L, Rescigno M, Bove LE, Klotz S, Ninet S. Observation of a Plastic Crystal in Water-Ammonia Mixtures under High Pressure and Temperature. J Phys Chem Lett 2023; 14:2301-2307. [PMID: 36847363 DOI: 10.1021/acs.jpclett.3c00092] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Solid mixtures of ammonia and water, the so-called ammonia hydrates, are thought to be major components of solar and extra-solar icy planets. We present here a thorough characterization of the recently reported high pressure (P)-temperature (T) phase VII of ammonia monohydrate (AMH) using Raman spectroscopy, X-ray diffraction, and quasi-elastic neutron scattering (QENS) experiments in the ranges 4-10 GPa, 450-600 K. Our results show that AMH-VII exhibits common structural features with the disordered ionico-molecular alloy (DIMA) phase, stable above 7.5 GPa at 300 K: both present a substitutional disorder of water and ammonia over the sites of a body-centered cubic lattice and are partially ionic. The two phases however markedly differ in their hydrogen dynamics, and QENS measurements show that AMH-VII is characterized by free molecular rotations around the lattice positions which are quenched in the DIMA phase. AMH-VII is thus a peculiar crystalline solid in that it combines three types of disorder: substitutional, compositional, and rotational.
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Affiliation(s)
- H Zhang
- Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie (IMPMC), Sorbonne Université, CNRS UMR 7590, MNHN, 4, place Jussieu, Paris 75005, France
- Shandong Key Laboratory of Optical Communication Science and Technology, School of Physics Science and Information Technology, Liaocheng University, Liaocheng 252059, China
| | - F Datchi
- Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie (IMPMC), Sorbonne Université, CNRS UMR 7590, MNHN, 4, place Jussieu, Paris 75005, France
| | - L Andriambariarijaona
- Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie (IMPMC), Sorbonne Université, CNRS UMR 7590, MNHN, 4, place Jussieu, Paris 75005, France
| | - M Rescigno
- Dipartimento di Fisica, Universita di Roma La Sapienza, Piazzale Aldo Moro 5, 00185 Roma, Italy
| | - L E Bove
- Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie (IMPMC), Sorbonne Université, CNRS UMR 7590, MNHN, 4, place Jussieu, Paris 75005, France
- Dipartimento di Fisica, Universita di Roma La Sapienza, Piazzale Aldo Moro 5, 00185 Roma, Italy
- LQM, Institute of Physics, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - S Klotz
- Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie (IMPMC), Sorbonne Université, CNRS UMR 7590, MNHN, 4, place Jussieu, Paris 75005, France
| | - S Ninet
- Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie (IMPMC), Sorbonne Université, CNRS UMR 7590, MNHN, 4, place Jussieu, Paris 75005, France
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2
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Abstract
The quest for a possible liquid-liquid coexistence line in supercooled water below its homogeneous nucleation temperature is faced by confining water within a porous silica substrate (MCM-41). This system is investigated by synchrotron radiation infrared spectroscopy, exploring both the intramolecular and the intermolecular vibrational dynamics, in the temperature range from ambient down to ∼120 K, along several isobaric paths between 0.7 kbar and 3.0 kbar. Upon lowering the temperature, the OH-stretching band shows that the intramolecular vibrational dynamics continuously evolves from predominantly liquidlike to predominantly icelike. An abrupt change in the line shape of the intermolecular vibrational band between 220 K and 240 K, depending on the pressure, is the signature of nucleation of ice within the MCM-41 pores. These findings do not support the presence of two liquid phases and provide evidence for the coexistence of liquid water and ice in water confined in MCM-41.
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Affiliation(s)
- E Stefanutti
- Sorbonne Université, Muséum National d'Histoire Naturelle, UMR CNRS 7590, IRD, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, IMPMC, 4 Place Jussieu, 75005 Paris, France
| | - L E Bove
- Sorbonne Université, Muséum National d'Histoire Naturelle, UMR CNRS 7590, IRD, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, IMPMC, 4 Place Jussieu, 75005 Paris, France
| | - F G Alabarse
- Sorbonne Université, Muséum National d'Histoire Naturelle, UMR CNRS 7590, IRD, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, IMPMC, 4 Place Jussieu, 75005 Paris, France
| | - G Lelong
- Sorbonne Université, Muséum National d'Histoire Naturelle, UMR CNRS 7590, IRD, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, IMPMC, 4 Place Jussieu, 75005 Paris, France
| | - F Bruni
- Dipartimento di Scienze, Università Degli Studi Roma Tre, Via della Vasca Navale 84, 00146 Roma, Italy
| | - M A Ricci
- Dipartimento di Scienze, Università Degli Studi Roma Tre, Via della Vasca Navale 84, 00146 Roma, Italy
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Stefanutti E, Bove LE, Lelong G, Ricci MA, Soper AK, Bruni F. Ice crystallization observed in highly supercooled confined water. Phys Chem Chem Phys 2019; 21:4931-4938. [DOI: 10.1039/c8cp07585a] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We investigate the state of water confined in the cylindrical pores of MCM-41 type mesoporous silica, with pore diameters of 2.8 nm and 4.5 nm, over the temperature range 160–290 K by combining small angle neutron scattering and wide angle diffraction.
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Affiliation(s)
- E. Stefanutti
- Dipartimento di Scienze, Università degli Studi Roma Tre
- 00146 Roma
- Italy
| | - L. E. Bove
- Sorbonne Université, Muséum National d'Histoire Naturelle, UMR CNRS 7590, IRD, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, IMPMC
- 75005 Paris
- France
| | - G. Lelong
- Sorbonne Université, Muséum National d'Histoire Naturelle, UMR CNRS 7590, IRD, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, IMPMC
- 75005 Paris
- France
| | - M. A. Ricci
- Dipartimento di Scienze, Università degli Studi Roma Tre
- 00146 Roma
- Italy
| | - A. K. Soper
- ISIS Department, UKRI-STFC Rutherford Appleton Laboratory, Harwell Campus
- Didcot
- UK
| | - F. Bruni
- Dipartimento di Scienze, Università degli Studi Roma Tre
- 00146 Roma
- Italy
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Ludl AA, Bove LE, Corradini D, Saitta AM, Salanne M, Bull CL, Klotz S. Probing ice VII crystallization from amorphous NaCl–D2O solutions at gigapascal pressures. Phys Chem Chem Phys 2017; 19:1875-1883. [DOI: 10.1039/c6cp07340a] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The high density amorphous solution NaCl·10.2D2O crystallises at 260 K as almost pure ice VII during annealing at gigapascal pressures.
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Affiliation(s)
- A.-A. Ludl
- Sorbonne Universités, UPMC Univ. Paris 06
- Paris
- France
- Departament d'FMC
- Universitat de Barcelona
| | - L. E. Bove
- Sorbonne Universités, UPMC Univ. Paris 06
- Paris
- France
- EPSL
- Institute of Condensed Matter Physics
| | - D. Corradini
- Sorbonne Universités
- UPMC Univ. Paris 06
- CNRS UMR 8234
- Paris
- France
| | - A. M. Saitta
- Sorbonne Universités, UPMC Univ. Paris 06
- Paris
- France
| | - M. Salanne
- Sorbonne Universités
- UPMC Univ. Paris 06
- CNRS UMR 8234
- Paris
- France
| | - C. L. Bull
- ISIS Facility
- STFC Rutherford Appleton Laboratory
- Harwell Science & Innovation Campus, Harwell Oxford
- Oxon, OX11 0QX
- UK
| | - S. Klotz
- Sorbonne Universités, UPMC Univ. Paris 06
- Paris
- France
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Klotz S, Komatsu K, Pietrucci F, Kagi H, Ludl AA, Machida S, Hattori T, Sano-Furukawa A, Bove LE. Ice VII from aqueous salt solutions: From a glass to a crystal with broken H-bonds. Sci Rep 2016; 6:32040. [PMID: 27562476 PMCID: PMC5000010 DOI: 10.1038/srep32040] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2016] [Accepted: 07/26/2016] [Indexed: 11/16/2022] Open
Abstract
It has been known for decades that certain aqueous salt solutions of LiCl and LiBr readily form glasses when cooled to below ≈160 K. This fact has recently been exploited to produce a « salty » high-pressure ice form: When the glass is compressed at low temperatures to pressures higher than 4 GPa and subsequently warmed, it crystallizes into ice VII with the ionic species trapped inside the ice lattice. Here we report the extreme limit of salt incorporation into ice VII, using high pressure neutron diffraction and molecular dynamics simulations. We show that high-pressure crystallisation of aqueous solutions of LiCl∙RH2O and LiBr∙RH2O with R = 5.6 leads to solids with strongly expanded volume, a destruction of the hydrogen-bond network with an isotropic distribution of water-dipole moments, as well as a crystal-to-amorphous transition on decompression. This highly unusual behaviour constitutes an interesting pathway from a glass to a crystal where translational periodicity is restored but the rotational degrees of freedom remaining completely random.
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Affiliation(s)
- S Klotz
- Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, CNRS UMR 7590, Université Pierre-et-Marie-Curie, F-75252 Paris, France
| | - K Komatsu
- Geochemical Research Center, Graduate School of Science, The University of Tokyo, Tokyo 113-0033, Japan
| | - F Pietrucci
- Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, CNRS UMR 7590, Université Pierre-et-Marie-Curie, F-75252 Paris, France
| | - H Kagi
- Geochemical Research Center, Graduate School of Science, The University of Tokyo, Tokyo 113-0033, Japan
| | - A-A Ludl
- Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, CNRS UMR 7590, Université Pierre-et-Marie-Curie, F-75252 Paris, France
| | - S Machida
- CROSS-Tokai, Research Centre for Neutron Science and Technology, 162-1 Shirakata, Tokai, Ibaraki 319-1106, Japan
| | - T Hattori
- J-PARC Center, Japan Atomic Energy Agency, Tokai, Naka, Ibaraki 319-1195, Japan
| | - A Sano-Furukawa
- J-PARC Center, Japan Atomic Energy Agency, Tokai, Naka, Ibaraki 319-1195, Japan
| | - L E Bove
- Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, CNRS UMR 7590, Université Pierre-et-Marie-Curie, F-75252 Paris, France.,Institute of Condensed Matter Physics, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
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Abstract
A systematic study of the properties of high-density amorphous ice (HDA) in the presence of increasing amounts of salt is missing, especially because it is challenging to avoid ice crystallization upon cooling the pressurized liquid. In order to be able to study HDA also in the presence of small amounts of salt, we have investigated the transformation behaviour of quenched aqueous LiCl solutions (mole fraction x < 0.25) upon pressurization in a piston-cylinder setup at 77 K. The sample properties were characterized by in situ dilatometry under high pressure conditions and after recovery by ex situ powder X-ray diffraction (XRD) and differential scanning calorimetry (DSC) at ambient pressure. Two regimes can be identified, with a rather sharp switch at about x = 0.12. At x < 0.12 the samples show the phenomenology also known for pure water samples. They are composed mainly of hexagonal ice (Ih) and experience pressure-induced amorphization to HDA at P > 1 GPa. The observed densification is consistent with the idea that a freeze concentrated LiCl solution of x = 0.14 (R = 6) segregates, which transforms to the glassy state upon cooling, and that the densification is only due to the Ih → HDA transition. Also the XRD patterns and DSC scans are almost unaffected by the presence of the segregated glassy LiCl solution. Upon heating at ambient pressure HDA experiences the polyamorphic transition to low-density amorphous ice (LDA) at ∼120 K, even at x ∼ 0.10. Based on the latent heat evolved in the transition we suggest that almost all water in the sample transforms to an LDA-like state, even the water in the vicinity of the ions. The glassy LiCl solution acts as a spectator that does not shift the transformation temperature significantly and experiences a glass-to-liquid transition at ∼140 K prior to the crystallization to cubic ice. By contrast, at x > 0.12 the phenomenology completely changes and is now dominated by the salt. Hexagonal ice no longer forms upon quenching the LiCl solution, but instead LDA forms. A broad pressure-induced transformation at >0.6 GPa can be attributed to the densification of LDA, the glassy LiCl solution and/or glassy hydrates.
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Affiliation(s)
- G N Ruiz
- Instituto de Química Física de los Materiales, Medio Ambiente y Energía (INQUIMAE-CONICET), Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Pabellón II, Ciudad Universitaria, (1428), Buenos Aires, Argentina
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Ludl AA, Bove LE, Saitta AM, Salanne M, Hansen TC, Bull CL, Gaal R, Klotz S. Structural characterization of eutectic aqueous NaCl solutions under variable temperature and pressure conditions. Phys Chem Chem Phys 2015; 17:14054-63. [PMID: 25955540 DOI: 10.1039/c5cp00224a] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The structure of amorphous NaCl solutions produced by fast quenching is studied as a function of pressure, up to 4 GPa, by combined neutron diffraction experiments and classical molecular dynamics simulations. Similarly to LiCl solutions the system amorphizes at ambient pressure in a dense phase structurally similar to the e-HDA phase in pure water. The measurement of the static structure factor as a function of pressure allowed us to validate a new polarizable force field developed by Tazi et al., 2012, never tested under non-ambient conditions. We infer from simulations that the hydration shells of Na(+) cations form well defined octahedra composed of both H2O molecules and Cl(-) anions at low pressure. These octahedra are gradually broken by the seventh neighbour moving into the shell of first neighbours yielding an irregular geometry. In contrast to LiCl solutions and pure water, the system does not show a polyamorphic transition under pressure. This confirms that the existence of polyamorphism relies on the tetrahedral structure of water molecules, which is broken here.
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Affiliation(s)
- A-A Ludl
- Sorbonne Universités, UPMC Univ Paris 06, CNRS, UMR 7590, IMPMC, F-75005, Paris, France.
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8
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Ayrinhac S, Gauthier M, Bove LE, Morand M, Le Marchand G, Bergame F, Philippe J, Decremps F. Equation of state of liquid mercury to 520 K and 7 GPa from acoustic velocity measurements. J Chem Phys 2014; 140:244201. [DOI: 10.1063/1.4882695] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Bove LE, Dreyfus C, Torre R, Pick RM. Observation of nanophase segregation in LiCl aqueous solutions from transient grating experiments. J Chem Phys 2014; 139:044501. [PMID: 23901987 DOI: 10.1063/1.4813283] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Transient grating experiments performed on supercooled LiCl, RH2O solutions with R > 6 reveal the existence of well resolved, short time, extra signal which superposes to the normal signal observed for the R = 6 solution and for homogenous glass forming systems. This extra signal shows up below 190 K, its shape and the associated timescale depend only on temperature, while its intensity increases with R. We show that the origin of this signal is a phase separation between clusters with a low solute concentration and the remaining, more concentrated, solution. Our analysis demonstrates that these clusters have a nanometer size and a composition which are rather temperature independent, while increasing R simply increases the density of these clusters.
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Affiliation(s)
- L E Bove
- IMPMC, Université P. et M. Curie et CNRS-UMR 7590, Paris, France
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Bove LE, Klotz S, Strässle T, Koza M, Teixeira J, Saitta AM. Translational and rotational diffusion in water in the Gigapascal range. Phys Rev Lett 2013; 111:185901. [PMID: 24237539 DOI: 10.1103/physrevlett.111.185901] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Indexed: 06/02/2023]
Abstract
First measurements of the self-dynamics of liquid water in the GPa range are reported. The GPa range has here become accessible through a new setup for the Paris-Edinburgh press specially conceived for quasielastic neutron scattering studies. A direct measurement of both the translational and rotational diffusion coefficients of water along the 400 K isotherm up to 3 GPa, corresponding to the melting point of ice VII, is provided and compared with molecular dynamics simulations. The translational diffusion is observed to strongly decrease with pressure, though its variation slows down for pressures higher than 1 GPa and decouples from that of the shear viscosity. The rotational diffusion turns out to be insensitive to pressure. Through comparison with structural data and molecular dynamics simulations, we show that this is a consequence of the rigidity of the first neighbors shell and of the invariance of the number of hydrogen bonds of a water molecule under high pressure. These results show the inadequacy of the Stokes-Einstein-Debye equations to predict the self-diffusive behavior of water at high temperature and high pressure, and challenge the usual description of hot dense water behaving as a simple liquid.
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Affiliation(s)
- L E Bove
- IMPMC, CNRS-UMR 7590, Université Pierre & Marie Curie, 75252 Paris, France and Ecole Polytech Fed Lausanne, Inst Condensed Matter Phys, EPSL, CH-1015 Lausanne, Switzerland
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Winkel K, Seidl M, Loerting T, Bove LE, Imberti S, Molinero V, Bruni F, Mancinelli R, Ricci MA. Structural study of low concentration LiCl aqueous solutions in the liquid, supercooled, and hyperquenched glassy states. J Chem Phys 2011; 134:024515. [PMID: 21241128 DOI: 10.1063/1.3528000] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Neutron diffraction experiments on a solution of LiCl in water (R = 40) at ambient conditions and in the supercooled and hyperquenched states are reported and analyzed within the empirical potential structure refinement framework. Evidence for the modifications of the microscopic structure of the solvent in the presence of such a small amount of salt is found at all investigated thermodynamic states. On the other hand, it is evident that the structure of the hyperquenched salty sample is similar to that of pure low density amorphous water, although all the peaks of the radial distribution functions are broader in the present case. Changes upon supercooling or hyperquenching of the ion's hydration shells and contacts are of limited size and evidence for segregation phenomena at these states does not clearly show up, although the presence of water separated contacts between ion of the same sign is intriguing.
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Affiliation(s)
- K Winkel
- Institute of Physical Chemistry, University of Innsbruck, Innrain 52a, 6020 Innsbruck, Austria
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Bove LE, Klotz S, Philippe J, Saitta AM. Pressure-induced polyamorphism in salty water. Phys Rev Lett 2011; 106:125701. [PMID: 21517327 DOI: 10.1103/physrevlett.106.125701] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2010] [Revised: 02/14/2011] [Indexed: 05/30/2023]
Abstract
We investigated the metastable phase diagram of an ionic salt aqueous solution, LiCl:6D₂O, at high pressure and low temperature by neutron diffraction measurements and computer simulations. We show that the presence of salt triggers a stepwise transformation, under annealing at high pressure, to a new very high-density amorphous form. The transition occurs abruptly at 120 K and 2 GPa, is reversible, and is characterized by a sizeable enthalpy release. Simulations suggest that the polyamorphic transition is linked to a local structural reorganization of water molecules around the Li ions.
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Affiliation(s)
- L E Bove
- IMPMC, CNRS-UMR 7590, Université P&M Curie, 75252 Paris, France
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13
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Abstract
We present incoherent quasielastic neutron scattering measurements on ice Ih (ordinary ice) and Ic (cubic ice) which show the existence of nonharmonic motion of hydrogen at low temperatures, down to 5 K. We show that this dynamics is localized, nonvibrational, and related to the hydrogen disorder since it is absent in ordered ice VIII. A main jump distance of 0.75 A is identified, hence close to the distance between the two possible proton sites along the oxygen-oxygen bond. The dynamics is non-Arrhenius, has a large time rate of 2.7x10(11) s-1, and affects only a few percent of the total number of hydrogen atoms in the crystal. These results give evidence for the existence of concerted proton tunneling in these ice phases.
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Affiliation(s)
- L E Bove
- IMPMC, CNRS-UMR 7590, Université P&M Curie, F-75252 Paris, France
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Bove LE, Catti M, Paciaroni A, Sacchetti F. Neutron Scattering Study of the Dynamics of Hydronium Ion in (H3O)Zr2(PO4)3 Nasicon Across the Order−Disorder Transition. J Phys Chem B 2004. [DOI: 10.1021/jp037463m] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- L. E. Bove
- Istituto Nazionale per la Fisica della Materia, Unità di Perugia, Dipartimento di Fisica, Università di Perugia, Via A. Pascoli, I-06123 Perugia, Italy, and Dipartimento di Scienza dei Materiali, Università di Milano Bicocca, via Cozzi 53, I-20125 Milano, Italy
| | - M. Catti
- Istituto Nazionale per la Fisica della Materia, Unità di Perugia, Dipartimento di Fisica, Università di Perugia, Via A. Pascoli, I-06123 Perugia, Italy, and Dipartimento di Scienza dei Materiali, Università di Milano Bicocca, via Cozzi 53, I-20125 Milano, Italy
| | - A. Paciaroni
- Istituto Nazionale per la Fisica della Materia, Unità di Perugia, Dipartimento di Fisica, Università di Perugia, Via A. Pascoli, I-06123 Perugia, Italy, and Dipartimento di Scienza dei Materiali, Università di Milano Bicocca, via Cozzi 53, I-20125 Milano, Italy
| | - F. Sacchetti
- Istituto Nazionale per la Fisica della Materia, Unità di Perugia, Dipartimento di Fisica, Università di Perugia, Via A. Pascoli, I-06123 Perugia, Italy, and Dipartimento di Scienza dei Materiali, Università di Milano Bicocca, via Cozzi 53, I-20125 Milano, Italy
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Bove LE, Sacchetti F, Petrillo C, Dorner B, Formisano F, Barocchi F. Neutron investigation of the ion dynamics in liquid mercury: evidence for collective excitations. Phys Rev Lett 2001; 87:215504. [PMID: 11736350 DOI: 10.1103/physrevlett.87.215504] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2001] [Indexed: 05/23/2023]
Abstract
The ion dynamics of liquid mercury was investigated by inelastic neutron scattering. By exploiting an optimized high-resolution ( approximately 1 meV) experimental configuration, the dynamic response function was accurately measured. Collective excitations extending up to 0.6 A(-1) were observed with an associated velocity of 2100+/-80 m/s. This value is notably greater than the sound velocity, but it is provided by a simple Bohm-Staver calculation. The latter finding emphasizes those electron-related features in the ion dynamics, which are common to systems as different as polyvalent and alkali metals.
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Affiliation(s)
- L E Bove
- INFM and Dipartimento di Fisica, Universitá di Perugia, I-06123 Perugia, Italy
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Bove LE, Sacchetti F, Petrillo C, Dorner B. Neutron investigation of collective excitations in liquid K-Cs alloys: the role of the electron density. Phys Rev Lett 2000; 85:5352-5355. [PMID: 11135994 DOI: 10.1103/physrevlett.85.5352] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2000] [Indexed: 05/23/2023]
Abstract
The investigation of the ion dynamics in the liquid alloy K52Cs48, which has the same electron density as Rb, was carried out by neutron inelastic scattering. Well defined collective excitations were observed up to the maximum value of momentum transfer of the experiment. A scaling of the dispersion relation data was found to hold between K-Cs alloys, Rb and Cs. The suggested scaling points out the key role of the conduction electron density in the collective dynamics of alkali metals.
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Affiliation(s)
- L E Bove
- Istituto Nazionale per la Fisica della Materia, Unita di Perugia, Perugia, Italy
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