Energy distributions of neutrons scattered from solid C60 by the beryllium detector method

1995 ◽  
Vol 73 (11-12) ◽  
pp. 763-771 ◽  
Author(s):  
J.R. D. Copley ◽  
D. A. Neumann ◽  
W. A. Kamitakahara
Keyword(s):  
Energy Range ◽  
First Principles ◽  
Spectroscopic Data ◽  
Vibrational Modes ◽  
First Principles Calculations ◽  
Energy Distributions ◽  
Gaussian Functions ◽  
Detector Method ◽  
Normal Vibrational Modes ◽  
Rich Spectrum

We measured the energy distribution of neutrons scattered from polycrystalline C60, using a high-resolution filter-analyzer spectrometer. In the energy range 30–90 meV (242–726 cm−1) we observed a rich spectrum that we fitted to a sum of 15 Gaussian functions, each of which is assigned to one or a set of several degenerate normal vibrational modes of the C60 molecule. We also observed two broad features in the energy range from 90–130 meV (726–1049 cm−1). Our results are generally in excellent agreement with published spectroscopic data. Detailed comparisons with the results of several first-principles calculations suggest that present-day theories can predict the internal vibrational frequencies of C60 rather well, at least in the 30–90 meV range of energies.

Vibrational Total Energy Distributions in Terms of Symmetry Coordinates, Forces and Momenta

1980 ◽  
Vol 35 (4) ◽  
pp. 464-465
Author(s):  
Alain J. P. Alix ◽  
Erling Rytter
Keyword(s):  
Total Energy ◽  
Polyatomic Molecules ◽  
Vibrational Modes ◽  
Energy Distributions ◽  
Symmetry Coordinates ◽  
Generalized Symmetry ◽  
Normal Vibrational Modes

Abstract The fundamental definitions of the Total Energy and of the Vibrational Total Energy Distributions are presented in details in terms of either symmetry coordinates, or generalised symmetry forces, or generalized symmetry coordinates. This, give now a uniform tool for physicists and chemists in the field of characterisation of the normal vibrational modes of polyatomic molecules.

scholarly journals Stability, diffusion, and complex formation of beryllium in wurtzite GaN

2000 ◽  
Vol 639 ◽  
Author(s):  
Sukit Limpijumnong ◽  
Chris G. Van de Walle ◽  
Jörg Neugebauer
Keyword(s):  
Complex Formation ◽  
First Principles ◽  
Formation Energy ◽  
Potential Problem ◽  
Vibrational Modes ◽  
First Principles Calculations ◽  
Experimental Identification ◽  
Donor Character ◽  
Formation Of Complexes

ABSTRACTWe have studied the properties of Be dopants in GaN using first principles calculations. Substitutional Be on a Ga site acts as an acceptor, but interstitial Be poses a potential problem because of its low formation energy and donor character. We study the diffusion of interstitial Be and find it to be highly anisotropic. We also study the formation of complexes between substitutional and interstitial Be, and between substitutional Be and hydrogen. We have calculated the Be-H vibrational modes to aid in experimental identification of such complexes.

Understanding global infrared opacity and hot bands of greenhouse molecules with low vibrational modes from first-principles calculations: the case of CF4

2018 ◽  
Vol 20 (32) ◽  
pp. 21008-21033 ◽  
Author(s):  
Michaël Rey ◽  
Iana S. Chizhmakova ◽  
Andrei V. Nikitin ◽  
Vladimir G. Tyuterev
Keyword(s):  
Global Warming ◽  
First Principles ◽  
Vibrational Modes ◽  
First Principles Calculations ◽  
Atmospheric Lifetime ◽  
The Future ◽  
Global Warming Potentials

Fluorine containing molecules have a particularly long atmospheric lifetime and their very big estimated global warming potentials are expected to rapidly increase in the future.

scholarly journals Potential Energy Landscape of CO Adsorbates on NaCl(100) and Implications in Isomerization of Vibrationally Excited CO

2020 ◽  
Author(s):  
Jun Chen ◽  
Seenivasan Hariharan ◽  
Joerg Meyer ◽  
Hua Guo
Keyword(s):  
Potential Energy ◽  
Energy Range ◽  
First Principles ◽  
Potential Energy Surfaces ◽  
Energy Landscape ◽  
First Principles Calculations ◽  
Small Energy ◽  
Vibrationally Excited ◽  
Potential Energy Landscape ◽  
Energy Surfaces

Several full-dimensional potential energy surfaces (PESs) are reported for vibrating CO adsorbates at two coverages on a rigid NaCl(100) surface based on first principles calculations. These PESs reveal a rather flat energy landscape for physisorption of vibrationless CO on NaCl(100), evidenced by various C-down adsorption patterns within a small energy range. Agreement with available experimental results is satisfactory, although quantitative differences exist. These PESs are used to explore isomerization pathways between the C-down and higher energy O-down configurations, which reveal a significant isomerization barrier. As CO vibration is excited, however, the energy order of the two isomer changes, which helps to explain the experimental observed flipping of vibrationally excited CO adsorbates.

scholarly journals Anomalous vibrational modes in few layer WTe 2 revealed by polarized Raman scattering and first-principles calculations

2D Materials ◽  
2017 ◽  
Vol 4 (3) ◽  
pp. 035024 ◽  
Author(s):  
Yan Cao ◽  
Natalya Sheremetyeva ◽  
Liangbo Liang ◽  
Hui Yuan ◽  
Tingting Zhong ◽  
...  
Keyword(s):  
Raman Scattering ◽  
First Principles ◽  
Vibrational Modes ◽  
First Principles Calculations ◽  
Polarized Raman
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