Shell-model calculations of the far-infrared optical properties of CsI

1977 ◽  
Vol 55 (3) ◽  
pp. 227-234 ◽  
Author(s):  
J. E. Eldridge ◽  
Roger Howard ◽  
P. R. Staal
Keyword(s):  
Optical Properties ◽  
Shell Model ◽  
Inelastic Neutron Scattering ◽  
Far Infrared ◽  
Inelastic Neutron ◽  
Dielectric Constants ◽  
Wave Number ◽  
Model Calculations ◽  
Resonance Wave ◽  
Infrared Optical Properties

The far-infrared optical properties of CsI, including the real and imaginary dielectric constants, absorption coefficient, refractive index, and reflectivity, have been calculated absolutely using shell-model lattice-dynamical data, fitted to dispersion curves measured by inelastic neutron scattering, as input to the calculations. The calculations were based on cubic anharmonicity only. The results show a marked improvement in the wave number position of certain structure in the optical properties over that previously obtained using deformation-dipole lattice-dynamical data. The agreement with experiment at 300, 77, 20, and 12 K is generally very good apart from the obvious need for quartic anharmonicity at higher temperatures, a discrepancy in the wave number shift applied to the resonance wave number, and a few details of structure predicted by the shell model and not observed experimentally.

scholarly journals Nuclear structure of Ge76 from inelastic neutron scattering measurements and shell model calculations

2017 ◽  
Vol 95 (1) ◽  
Author(s):  
S. Mukhopadhyay ◽  
B. P. Crider ◽  
B. A. Brown ◽  
S. F. Ashley ◽  
A. Chakraborty ◽  
...  
Keyword(s):  
Neutron Scattering ◽  
Shell Model ◽  
Nuclear Structure ◽  
Inelastic Neutron Scattering ◽  
Inelastic Neutron ◽  
Model Calculations ◽  
Scattering Measurements

Far Infrared Optical Properties of Amorphous As–Se System

1982 ◽  
Vol 21 (Part 1, No. 3) ◽  
pp. 418-423 ◽  
Author(s):  
Seinosuke Onari ◽  
Osamu Sugino ◽  
Michio Kato ◽  
Toshihiro Arai
Keyword(s):  
Optical Properties ◽  
Far Infrared ◽  
Infrared Optical Properties

Low-frequency single-crystal Raman, far-infrared, and inelastic neutron scattering studies of acetanilide at low temperature

1991 ◽  
Vol 95 (13) ◽  
pp. 5281-5286 ◽  
Author(s):  
Clifford T. Johnston ◽  
Stephen F. Agnew ◽  
Juergen Eckert ◽  
Llewellyn H. Jones ◽  
Basil I. Swanson ◽  
...  
Keyword(s):  
Low Temperature ◽  
Neutron Scattering ◽  
Single Crystal ◽  
Inelastic Neutron Scattering ◽  
Low Frequency ◽  
Far Infrared ◽  
Inelastic Neutron

scholarly journals Raman active modes of single-wall boron nitride nanotubes inside carbon nanotubes

2018 ◽  
Vol 3 (2) ◽  
Author(s):  
A.M. Nassir ◽  
Ah Rahmani ◽  
M. Boutahir ◽  
B. Fakrach ◽  
H. Chadli ◽  
...  
Keyword(s):  
Boron Nitride ◽  
Inelastic Neutron Scattering ◽  
Large Diameter ◽  
Chemical Properties ◽  
Spatial Dimension ◽  
Inelastic Neutron ◽  
Boron Nitride Nanotubes ◽  
Hybrid Nanostructures ◽  
Wave Number ◽  
Physical And Chemical

The structure of boron–nitride nanotubes (BNNTs) is very similar to that of CNTs, and they exhibit many similar physical and chemical properties. In particular, a single walled boron nitride nanotube (BNNT) and a single walled carbon nanotube (CNT) have been reported. The spectral moment’s method (SMM) was shown to be a powerful tool for determining vibrational spectra (infrared absorption, Raman scattering and inelastic neutron-scattering spectra) of harmonic systems. This method can be applied to very large systems, whatever the type of atomic forces, the spatial dimension, and structure of the material. The calculations of vibrational properties of BNNT@CNT double-walled hybrid nanostructures are performed in the framework of the force constants model, using the spectral moment's method (SMM). A Lennard–Jones potential is used to describe the van der Waals in-teractions between inner and outer tubes in hybrid systems. The calculation of the BNNT@CNT Raman active modes as a function of the diameter and chirality of the inner and outer tubes allows us to derive the diameter dependence of the wave number of the breathing-like modes, intermediate-like modes and tangential-like modes in a large diameter range. These predictions are useful to interpret the experimental data.

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