Diamond (C) temperature dependence of phonon self energy, frequency dependence of the damping function

2005 ◽  
pp. 1-7
Author(s):  
Keyword(s):  
Temperature Dependence ◽  
Frequency Dependence ◽  
Damping Function ◽  
Self Energy

Local Basis Gw Calculations and the Dielectric Response of Si and C Clusters

1999 ◽  
Vol 579 ◽  
Author(s):  
Ming Yu ◽  
Sergio E. Ulloa ◽  
Sang H. Yang
Keyword(s):  
Optical Properties ◽  
Frequency Dependence ◽  
Dielectric Response ◽  
Energy Operator ◽  
The Self ◽  
Response Functions ◽  
Gw Approximation ◽  
Dielectric Response Function ◽  
Self Energy ◽  
Dynamical Simulations

ABSTRACTWe describe our progress in developing an ab initio computational scheme for the calculation of the dielectric response function of solids, with special emphasis here on Si and C clusters. All calculations are carried out employing a basis of localized atomic-like orbitals and include the evaluation of quasiparticle corrections. The self-energy operator is evaluated in the GW approximation, with a full frequency dependence for the dielectric matrix. The approach is convenient and computationally optimal for the calculation of optical properties of complex systems lacking full periodicity, such as surfaces and clusters. We present here the dielectric response functions of clusters with structures found after full equilibration via molecular dynamical simulations, and discuss the sensitivity of the optical properties to quasiparticle corrections.

Frequency Dependence of the Damping Function of the SoftE-Symmetry Phonon in PbTiO3

1975 ◽  
Vol 34 (14) ◽  
pp. 886-889 ◽  
Author(s):  
D. Heiman ◽  
S. Ushioda ◽  
J. P. Remeika
Keyword(s):  
Frequency Dependence ◽  
Damping Function

Frequency-and Temperature-Dependence of Second Refractivity Virial Coefficients

1993 ◽  
Vol 48 (3) ◽  
pp. 505-513
Author(s):  
Uwe Hohm
Keyword(s):  
Temperature Dependence ◽  
Small Molecules ◽  
Frequency Dependence ◽  
Virial Coefficient ◽  
Virial Coefficients ◽  
Heuristic Approach ◽  
Experimental Values

Abstract A reasonable heuristic extrapolation of a theory given by Buckingham is used to estimate the frequency-and temperature-dependence of the second refractivity virial coefficient. The calculations are carried out for the atoms He, Ne, Ar, Kr, Xe and the small molecules H2 , N2 , O2 , HCl, CO2 , N2O, NH3 , CH4 , C2H4 , and SF6 . In some cases the frequency-dependence of BR (ω, T) is compared with experimental values, showing sometimes considerable deviations between experiment and the heuristic approach used in this work.

The frequency dependence of the soft mode anharmonic self-energy in KTaO3and SrTiO3

1978 ◽  
Vol 21 (1) ◽  
pp. 377-378 ◽  
Author(s):  
K. F. Pai ◽  
T. J. Parker ◽  
R. P. Lowndes
Keyword(s):  
Frequency Dependence ◽  
Soft Mode ◽  
Self Energy

ANALYSIS OF THE FREQUENCY SHIFT AND THE LINEWIDTH AS A FUNCTION OF TEMPERATURE IN SOLID NITROGEN

2011 ◽  
Vol 25 (27) ◽  
pp. 3679-3689 ◽  
Author(s):  
M. KURT ◽  
H. YURTSEVEN
Keyword(s):  
Experimental Data ◽  
Frequency Shift ◽  
Temperature Dependence ◽  
Functional Form ◽  
Fluorescence Method ◽  
Self Energy ◽  
Α Phase ◽  
Solid Nitrogen ◽  
Functional Forms ◽  
Fluorescence Line

The temperature dependence of the frequency shift and the linewidth is studied using the expressions derived from the anharmonic self-energy. The functional form of the frequency shift is fitted in this study to the experimental data for the R 1 fluorescence line of ruby sample as a function temperature at zero pressure, instead of using empirical ν–P and ν–T relations in the ruby fluorescence method as given in the literature, in particular, for the solid nitrogen. We also demonstrate in this study the temperature dependence of the Eg librational frequency and its linewidth by fitting the functional forms of both frequency shift and the linewidth to the experimental data for the α phase of solid nitrogen.

TEMPERATURE DEPENDENCE OF THE RAMAN FREQUENCIES IN THE γ AND β PHASES OF SOLID NITROGEN

2010 ◽  
Vol 24 (31) ◽  
pp. 6069-6078 ◽  
Author(s):  
H. YURTSEVEN ◽  
T. TUNAY
Keyword(s):  
Experimental Data ◽  
Frequency Shift ◽  
Temperature Dependence ◽  
Interaction Mechanism ◽  
Internal Mode ◽  
Unusual Behavior ◽  
Self Energy ◽  
Solid Nitrogen ◽  
Increasing Temperature ◽  
Lattice Modes

We study here the Raman frequencies of the lattice modes (γ and β phases) and of an internal mode (γ phase) as a function of temperature in solid nitrogen. The frequency shift derived from the anharmonic self energy, is fitted to the experimental data for the Raman frequencies of the modes considered here in the γ and β phases of solid nitrogen. From our fittings, we find that the Raman frequencies of the lattice modes decrease, whereas those of the internal mode increase with increasing temperature in solid nitrogen. The unusual behavior of the internal mode indicates that the interaction mechanism should be different in relation to the anharmonicity in the γ phase of solid nitrogen.

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