Vibrational properties and infrared spectra ofAlxGa1−xAs systems. I. Average-t-matrix approximation versus supercell calculation for homogeneous alloys

1991 ◽  
Vol 43 (18) ◽  
pp. 14447-14456 ◽  
Author(s):  
M. Bernasconi ◽  
L. Colombo ◽  
L. Miglio ◽  
G. Benedek
Keyword(s):  
Infrared Spectra ◽  
Vibrational Properties ◽  
Matrix Approximation ◽  
T Matrix ◽  
Supercell Calculation

Momentum distribution and the universal contact of a unitary Fermi gas with particle-hole fluctuation

2018 ◽  
Vol 32 (21) ◽  
pp. 1850249 ◽  
Author(s):  
Xiao-Xia Ruan ◽  
Hao Gong ◽  
Zheng-Ling Wang ◽  
Hong-Shi Zong
Keyword(s):  
Experimental Data ◽  
Momentum Distribution ◽  
Fermi Gas ◽  
Normal Phase ◽  
Large Momentum ◽  
Matrix Approximation ◽  
Self Consistent ◽  
Theoretical Predictions ◽  
Unitary Fermi Gas ◽  
T Matrix

We compute the momentum distribution of a homogeneous Fermi gas at unitarity in the normal phase within the framework of the non-self-consistent T-matrix approximation with particle-hole fluctuation. From the large-momentum behavior of momentum distribution, we obtain the contact for the unitary Fermi gas. We also compare our results with experimental data and other theoretical predictions.

scholarly journals Vibrational properties of isotopically enriched materials: the case of calcite

RSC Advances ◽  
2018 ◽  
Vol 8 (59) ◽  
pp. 33985-33992
Author(s):  
Ben Xu ◽  
Anna Hirsch ◽  
Leeor Kronik ◽  
Kristin M. Poduska
Keyword(s):  
Infrared Spectra ◽  
Vibrational Properties ◽  
Isotopic Enrichment ◽  
Low Levels

Isotopic enrichment in calcite, even at relatively low levels, can produce surprising changes to infrared spectra.

First-Principles Study of Structural and Vibrational Properties of α-SiO2 under Pressure

2015 ◽  
Vol 775 ◽  
pp. 191-196
Author(s):  
Xiao Wei Lei ◽  
Yong Song ◽  
Kuo Yang ◽  
Hui Zhao
Keyword(s):  
High Pressure ◽  
Perturbation Theory ◽  
Infrared Spectra ◽  
First Principles ◽  
Linear Response ◽  
Density Functional ◽  
Vibrational Properties ◽  
Vibrational Modes ◽  
Density Functional Perturbation Theory ◽  
Good Agreement

Using first principles approach, we present the structural, vibrational and dielectric properties of α-SiO2. The calculations have been carried out within the density functional perturbation theory and linear response formalism using the norm-concerving pseudopotentials and a plane wave basis. All the vibrational modes identified are in good agreement with experiment. The calculated infrared spectra are also in good agreement with available experimental results both for the positions and the intensities of the main peaks. We find that the modes Eu7 and A2u4 splits in two respectively at high hydrostaticpressures. Then we calculate the infrared spectra under high pressure of different orientations. The vibrational modes in different phase transitions are reported and discussed respectively.

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