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Banks PA, Kleist EM, Ruggiero MT. Investigating the function and design of molecular materials through terahertz vibrational spectroscopy. Nat Rev Chem 2023; 7:480-495. [PMID: 37414981 DOI: 10.1038/s41570-023-00487-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/13/2023] [Indexed: 07/08/2023]
Abstract
Terahertz spectroscopy has proved to be an essential tool for the study of condensed phase materials. Terahertz spectroscopy probes the low-frequency vibrational dynamics of atoms and molecules, usually in the condensed phase. These nuclear dynamics, which typically involve displacements of entire molecules, have been linked to bulk phenomena ranging from phase transformations to semiconducting efficiency. The terahertz region of the electromagnetic spectrum has historically been referred to as the 'terahertz gap', but this is a misnomer, as there exist a multitude of methods for accessing terahertz frequencies, and now there are cost-effective instruments that have made terahertz studies much more user-friendly. This Review highlights some of the most exciting applications of terahertz vibrational spectroscopy so far, and provides an in-depth overview of the methods of this technique and its utility to the study of the chemical sciences.
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Affiliation(s)
- Peter A Banks
- Department of Chemistry, University of Vermont, Burlington, VT, USA
| | - Elyse M Kleist
- Department of Chemistry, University of Vermont, Burlington, VT, USA
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Peng J, Zhang S, Refson K, Dove MT. Unique features of the structural phase transition in acetylene showing simultaneous characteristics of reconstructive, displacive and order-disorder. Phys Chem Chem Phys 2023; 25:9909-9924. [PMID: 36946889 DOI: 10.1039/d3cp00400g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/18/2023]
Abstract
We have studied the two phases of the molecular crystal acetylene, C2H2, using calculations of the lattice dynamics by Density Functional Theory methods. together with the use of classical molecular dynamics (MD) simulation methods. The two phases share the same simple face-centred cubic lattice arrangement of the molecular centres of mass, but with different molecular orientations. We show that the higher-temperature phase has lower phonon frequencies and hence higher entropy, giving thermodynamic stability at higher temperature. The calculated lattice dynamics of this phase show instabilities associated with phonons involving pure rotations of the molecules. The MD results show large amplitudes of librational motion in this phase. The MD simulations also showed a potential phase transition to a structure of tetragonal symmetry. The picture that emerges is that the phase transition in acetylene is a very rare example of one that encompasses elements of three types of transition: displacive, order-disorder and reconstructive.
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Affiliation(s)
- Jie Peng
- College of Physics, Sichuan University, Chengdu, Sichuan 610065, China
| | - Sijie Zhang
- Guizhou University of Engineering Science, Xueyan Road, Bijie, Guizhou, 55170, China
- College of Physics, Sichuan University, Chengdu, Sichuan 610065, China
| | - Keith Refson
- ISIS Facility, Harwell Campus, Chilton, Didcot, OX11 0QX, UK
| | - Martin T Dove
- College of Computer Science, Sichuan University, Chengdu, Sichuan 610065, China.
- School of Mechanical Engineering, Dongguan University of Technology, 1st Daxue Road, Songshan Lake, Dongguan, Guangdong 523000, China
- School of Physical and Chemical Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS, UK.
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Sharafi Zamir S, Fathi B, Ajji A, Robert M, Elkoun S. Crystallinity and Gas Permeability of Poly (Lactic Acid)/Starch Nanocrystal Nanocomposite. Polymers (Basel) 2022; 14:polym14142802. [PMID: 35890578 PMCID: PMC9323136 DOI: 10.3390/polym14142802] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Revised: 06/27/2022] [Accepted: 06/30/2022] [Indexed: 02/04/2023] Open
Abstract
The present work seeks to determine the impact of weight percentage (wt%) of grafted starch nanocrystals (g-SNCs) on the oxygen and water vapour permeability of poly (lactic acid), PLA. Changes in the oxygen and water vapour permeability of PLA due to changes in PLA’s crystalline structures and lamellar thickness were quantified. To this end, 3, 5, and 7 wt% of g-SNC nanoparticles were blended with PLA using the solvent casting method in order to study impact of g-SNC nanoparticles on crystallization behaviour, long spacing period, melting behavior, and oxygen and water barrier properties of PLA nanocomposites. This was achieved by wide-angle X-ray diffraction (WAXD), small-angle X-ray diffraction (SAXD), differential scanning calorimetry (DSC), and oxygen and water vapour permeability machine. The results of the WAXD and SAXD analysis show that the addition of 5 wt% g-SNC in PLA induces α crystal structure at a lower crystallization time, while it significantly increases the α crystal thickness of PLA, in comparison to neat PLA. However, when g-SNC concentrations were altered (i.e., 3 or 7 wt%), the crystallization time was found to increase due to the thermodynamic barrier of crystallization. Finally, the oxygen and water vapour permeability of PLA/SNC-g-LA (5 wt%) nanocomposite film were found to be reduced by ∼70% and ~50%, respectively, when compared to the neat PLA film. This can lead to the development of PLA nanocomposites with high potential for applications in food packaging.
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Affiliation(s)
- Somayeh Sharafi Zamir
- Department of Chemical and Biotechnological Engineering, University of Sherbrooke, Sherbrooke, QC J1K 2R1, Canada; (B.F.); (M.R.); (S.E.)
- Department of Chemistry, University of McGill, Montreal, QC J1K 2R1, Canada
- Correspondence: ; Tel.: +1-819-588-1095
| | - Babak Fathi
- Department of Chemical and Biotechnological Engineering, University of Sherbrooke, Sherbrooke, QC J1K 2R1, Canada; (B.F.); (M.R.); (S.E.)
| | - Abdellah Ajji
- 3SPack, CREPEC, Chemical Engineering Department, Polytechnique Montreal, Montreal, QC H3C 3A7, Canada;
| | - Mathieu Robert
- Department of Chemical and Biotechnological Engineering, University of Sherbrooke, Sherbrooke, QC J1K 2R1, Canada; (B.F.); (M.R.); (S.E.)
| | - Said Elkoun
- Department of Chemical and Biotechnological Engineering, University of Sherbrooke, Sherbrooke, QC J1K 2R1, Canada; (B.F.); (M.R.); (S.E.)
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Brehm M, Thomas M, Gehrke S, Kirchner B. TRAVIS—A free analyzer for trajectories from molecular simulation. J Chem Phys 2020; 152:164105. [DOI: 10.1063/5.0005078] [Citation(s) in RCA: 164] [Impact Index Per Article: 41.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Affiliation(s)
- M. Brehm
- Institut für Chemie, Martin-Luther-Universität Halle–Wittenberg, von-Danckelmann-Platz 4, D-06120 Halle (Saale), Germany
| | - M. Thomas
- Institut für Chemie, Martin-Luther-Universität Halle–Wittenberg, von-Danckelmann-Platz 4, D-06120 Halle (Saale), Germany
| | - S. Gehrke
- Mulliken Center for Theoretical Chemistry, Rheinische Friedrich-Wilhelms-Universität Bonn, Beringstr. 4+6, D-53115 Bonn, Germany
| | - B. Kirchner
- Mulliken Center for Theoretical Chemistry, Rheinische Friedrich-Wilhelms-Universität Bonn, Beringstr. 4+6, D-53115 Bonn, Germany
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Zhang F, Wang HW, Tominaga K, Hayashi M, Sasaki T. Terahertz Fingerprints of Short-Range Correlations of Disordered Atoms in Diflunisal. J Phys Chem A 2019; 123:4555-4564. [PMID: 31038953 DOI: 10.1021/acs.jpca.9b00580] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
This work proposes a terahertz (THz) spectroscopy approach to the investigation of one of the outstanding problems in crystallography-the structure analysis of a crystal with disorder. Form I of diflunisal, in which the two ortho sites on one phenyl ring of diflunisal show occupational disorder, was used for an illustration. THz radiation interacts with the collective vibrations of correlated disorder, thus providing a promising tool to examine the symmetry of short-range correlations of disordered atoms. Through a thorough examination of the selection rule of THz vibrations in which the disordered atoms are involved to different extents, we deduced that only four short-range correlation possibilities of disorder exist and all of them display unambiguous fingerprint peaks in the 50-170 cm-1 frequency region. We finally proposed an alternating packing model in which the correlation lengths of disorder are on the nanometer scale.
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Affiliation(s)
- Feng Zhang
- Molecular Photoscience Research Center , Kobe University , Nada, Kobe 657-0013 , Japan
| | - Houng-Wei Wang
- Center for Condensed Matter Sciences , National Taiwan University , 1 Roosevelt Rd., Sec. 4 , Taipei 10617 , Taiwan
| | - Keisuke Tominaga
- Molecular Photoscience Research Center , Kobe University , Nada, Kobe 657-0013 , Japan
| | - Michitoshi Hayashi
- Center for Condensed Matter Sciences , National Taiwan University , 1 Roosevelt Rd., Sec. 4 , Taipei 10617 , Taiwan
| | - Tetsuo Sasaki
- Research Institute of Electronics , Shizuoka University , Hamamatsu , Shizuoka 432-8011 , Japan
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Fan S, Ruggiero MT, Song Z, Qian Z, Wallace VP. Correlation between saturated fatty acid chain-length and intermolecular forces determined with terahertz spectroscopy. Chem Commun (Camb) 2019; 55:3670-3673. [PMID: 30855614 DOI: 10.1039/c9cc00141g] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
We measured crystalline (C-form) saturated fatty acids with even carbon numbers ranging from 12 to 20 using temperature dependent terahertz time-domain spectroscopy (THz-TDS). Absorption features between 0.5 and 3 THz were identified at temperatures from 96 K to 293 K, and a systematic red-shift was obvserved with the increasing carbon chain length. The origins of these absorption bands were uncovered using state-of-the-art ab initio density functional theory (DFT) calculations. Similar vibrational motions in the absorption bands of the different materials highlight the unique role that THz-TDS has for probing weak non-covalent interactions in these materials. Our results showcase the utility of the terahertz region, which is beyond the scope of related vibrational techniques, providing direct evidence of the effect of chain length on the intermolecular interactions of these molecules.
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Affiliation(s)
- Shuting Fan
- College of Electronic Science and Technology, Shenzhen University, 3688 Nanhai Rd, Shenzhen, Guangdong Province 518060, China.
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