scholarly journals Exotic Spectra and Lattice Vibrations of Ice X Using the DFT Method

Molecules ◽  
2018 ◽  
Vol 23 (11) ◽  
pp. 2780 ◽  
Author(s):  
Lu Jiang ◽  
Shu-Kai Yao ◽  
Kai Zhang ◽  
Ze-Ren Wang ◽  
Hui-Wen Luo ◽  
...  
Keyword(s):  
Vibrational Spectrum ◽  
Inelastic Neutron Scattering ◽  
Harmonic Approximation ◽  
Normal Modes ◽  
Dft Method ◽  
Inelastic Neutron ◽  
Lattice Vibrations ◽  
Ideal Crystal ◽  
Two Peaks ◽  
Ice Phase

A typical vibrational spectrum in the ice phase has four separate bands: Translation, libration, bending, and stretching. Ice X, the final ice phase under high pressure, shows an exotic vibrational spectrum. Based on harmonic approximation, an ideal crystal of ice X has one peak, at 998 cm−1, for Raman scattering and two peaks, at 450 cm−1 and 1507 cm−1, for infrared absorption in this work. These three characteristic peaks are indicators of the phase transition between ice VII and VIII and ice X. Despite many experimental and theoretical works on ice X, only this study has clearly indicated these characteristic peaks in the region of the IR band. The phonon density of states shows quite different features than ice VIII, which could be verified by inelastic neutron scattering in the future. The dynamic processes of 15 vibrational normal modes are discussed and the typical hydrogen bonds are missing.

scholarly journals Exotic spectra and lattice vibrations of ice X using the DFT method

2018 ◽  
Author(s):  
Lu Jiang ◽  
Shu-Kai Yao ◽  
Kai Zhang ◽  
Ze-Ren Wang ◽  
Hui-Wen Luo ◽  
...  
Keyword(s):  
Vibrational Spectrum ◽  
Inelastic Neutron Scattering ◽  
Normal Modes ◽  
Dft Method ◽  
Theoretical Work ◽  
Inelastic Neutron ◽  
Lattice Vibrations ◽  
Ideal Crystal ◽  
Two Peaks ◽  
Ice Phase

A typical vibrational spectrum in the ice phase has four separate bands: translation, libration, bending and stretching. Ice X, the final ice phase under high pressure, shows an exotic vibrational spectrum. Theoretically, an ideal crystal of ice X only has one peak at 998 cm-1 for Raman scattering and two peaks at 450 cm-1 and 1507 cm-1 for infrared absorption in this work. These three characteristic peaks are indicators of the phase transition between ice VII/VIII and ice X. Despite much experimental and theoretical work on ice X, only this study has clearly indicated these characteristic peaks in the region of the IR band. The phonon density of states shows quite different features than ice VIII, which could be verified by inelastic neutron scattering in the future. The dynamic processes of 15 vibrational normal modes are discussed and the typical hydrogen bonds are missing.

scholarly journals Computing analysis of lattice vibrations of ice VIII

RSC Advances ◽  
2017 ◽  
Vol 7 (51) ◽  
pp. 31789-31794 ◽  
Author(s):  
Shu-Kai Yao ◽  
Peng Zhang ◽  
Ying Zhang ◽  
Ying-Bo Lu ◽  
Tian-Lin Yang ◽  
...  
Keyword(s):  
Neutron Scattering ◽  
Dynamic Process ◽  
Inelastic Neutron Scattering ◽  
Lattice Vibration ◽  
Normal Modes ◽  
Inelastic Neutron ◽  
Simulation Methods ◽  
Lattice Vibrations ◽  
Photon Scattering ◽  
Computing Simulation

We devise an approach to link inelastic neutron scattering with photon scattering experiments by computing simulation methods. The dynamic process of 33 normal modes of lattice vibration of Ice VIII are precisely illustrated based on CASTEP code.

scholarly journals DFT Simulations of the Vibrational Spectrum and Hydrogen Bonds of Ice XIV

Molecules ◽  
2018 ◽  
Vol 23 (7) ◽  
pp. 1781 ◽  
Author(s):  
Kai Zhang ◽  
Peng Zhang ◽  
Ze-Ren Wang ◽  
Xu-Liang Zhu ◽  
Ying-Bo Lu ◽  
...  
Keyword(s):  
Vibrational Spectrum ◽  
Normal Vibration ◽  
Density Functional ◽  
Inelastic Neutron Scattering ◽  
General Rule ◽  
Experimental Spectrum ◽  
Inelastic Neutron ◽  
Functional Theory ◽  
Ir And Raman ◽  
Normal Vibration Frequencies

It is always a difficult task to assign the peaks recorded from a vibrational spectrum. Herein, we explored a new pathway of density functional theory (DFT) simulation to present three kinds of spectra of ice XIV that can be referenced as inelastic neutron scattering (INS), infrared (IR), and Raman experimental spectrum. The INS spectrum is proportional to the phonon density of states (PDOS) while the photon scattering signals reflect the normal vibration frequencies near the Brillouin zone (BZ) center. Based on good agreements with the experimental data, we identified the relative frequency and made scientific assignments through normal vibration modes analysis. The two hydrogen bond (H-bond) peaks among the ice phases from INS were discussed and the dynamic process of the H-bond vibrations was found to be classified into two basic modes. We deduced that two H-bond modes are a general rule among the ice family and more studies are ongoing to investigate this subject.

scholarly journals The vibrational spectrum of solid ferrocene by inelastic neutron scattering

2000 ◽  
Vol 112 (24) ◽  
pp. 10926-10929 ◽  
Author(s):  
E. Kemner ◽  
I. M. de Schepper ◽  
G. J. Kearley ◽  
U. A. Jayasooriya
Keyword(s):  
Vibrational Spectrum ◽  
Neutron Scattering ◽  
Inelastic Neutron Scattering ◽  
Inelastic Neutron

The crystal dynamics of lead sulphide

1967 ◽  
Vol 300 (1461) ◽  
pp. 210-217 ◽  
Keyword(s):  
Inelastic Neutron Scattering ◽  
Normal Modes ◽  
Lead Telluride ◽  
Alkali Halides ◽  
Inelastic Neutron ◽  
High Symmetry ◽  
Lead Sulphide ◽  
Shell Models ◽  
Longitudinal Optic

The frequencies of normal modes propagating in the high symmetry directions, [001], [110] and [111], of lead sulphide have been measured by inelastic neutron scattering techniques. A marked decrease in the value of the longitudinal optic mode frequency has been observed at small wavevectors. A similar effect has been reported in lead telluride, and is attributable to the screening of the macroscopic electric field by the free carriers in the crystal. The longitudinal optic mode frequencies have been estimated for the particular case of zero carrier concentration. The corrected frequencies have been used to deduce the parameters of rigid ion models and shell models for the interatomic forces of lead sulphide. The quality of the fit for both types of models is less satisfactory than for the equivalent models used for the alkali halides, but is comparable with those obtained for lead telluride. The best model gives a good fit to the frequencies, and has been used to calculate the frequency distribution and specific heat of lead sulphide. There is a marked similarity between some of the models of lead sulphide and lead telluride. One of these models has been used to calculate dispersion curves for lead selenide, and fair agreement has been obtained with the available experimental data.

scholarly journals The vibrational spectrum of indole: An inelastic neutron scattering study

2008 ◽  
Vol 345 (2-3) ◽  
pp. 230-238 ◽  
Author(s):  
John Tomkinson ◽  
Jennifer Riesz ◽  
Paul Meredith ◽  
Stewart F. Parker
Keyword(s):  
Vibrational Spectrum ◽  
Neutron Scattering ◽  
Inelastic Neutron Scattering ◽  
Inelastic Neutron ◽  
Scattering Study ◽  
Neutron Scattering Study
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