Statistical perturbation theory of order-disorder ferroelectrics: First perturbative correction

1971 ◽  
Vol 48 (2) ◽  
pp. 689-698
Author(s):  
R. E. Nettleton
Keyword(s):  
Perturbation Theory ◽  
Perturbative Correction ◽  
Statistical Perturbation

On the Operator Formulation of the Polyatomic Molecule Partition Function

1983 ◽  
Vol 38 (2) ◽  
pp. 167-183 ◽  
Author(s):  
J. Bohmann ◽  
W. Witschel
Keyword(s):  
Perturbation Theory ◽  
Partition Function ◽  
Polyatomic Molecule ◽  
Perturbation Series ◽  
Numerical Calculations ◽  
Model Systems ◽  
Coriolis Coupling ◽  
Commuting Operators ◽  
Operator Form ◽  
Statistical Perturbation

Abstract The Nielsen Hamiltonian of the general polyatomic molecule including anharmonicity and its resonances, Coriolis-coupling and its resonances, and rotation-vibration interaction are treated by statistical perturbation theory in its operator form. By generating function methods and operator theorems, which are treated in an appendix, cumbersome calculations with non-commuting operators are avoided. The results for H2O and SO2 agree very well with accurate numerical calculations from the literature. Qualitative conclusions on the convergence of the perturbation series are drawn from the numerical calculations for model systems.

THEORETICAL INVESTIGATIONS OF PROPERTIES OF HYDROGEN AND HELIUM MIXTURE BASED ON PERTURBATION THEORY

2012 ◽  
Vol 26 (15) ◽  
pp. 1250103 ◽  
Author(s):  
S. M. MOTEVALLI ◽  
M. R. PAHLAVANI ◽  
M. AZIMI
Keyword(s):  
Monte Carlo Simulation ◽  
Perturbation Theory ◽  
Yukawa Potential ◽  
Simulation Methods ◽  
Fluid Mixture ◽  
Helium Concentration ◽  
Theoretical Investigations ◽  
Helium Mixture ◽  
Double Yukawa Potential ◽  
Statistical Perturbation

In this paper, we have investigated thermodynamic parameters of hydrogen and helium fluid mixture with assistance of statistical perturbation theory. The results have been compared with existing theoretical and Monte Carlo simulation methods based. Moreover, the effects of density, temperature and helium concentration on equation of state (EOS) of this mixture have been considered. Likewise, since exp-6 potential has given better results in comparison with MC simulations in higher temperatures than double Yukawa potential and avoiding any vague speculation, comparison between effects of these potentials has been presented. The results further suggest that EOS in this place depends sensitively on the density, the potential function and concentration of each component.

A Perturbation Theory for the Population of Atomic Energy Levels in Non-Lte Plasmas

1988 ◽  
Vol 102 ◽  
pp. 343-347
Author(s):  
M. Klapisch
Keyword(s):  
Perturbation Theory ◽  
Small Parameter ◽  
Classification Scheme ◽  
Sum Rules ◽  
Energy Levels ◽  
Natural Classification ◽  
Quantum Numbers ◽  
Formal Expansion ◽  
Atomic Energy Levels ◽  
As Effects

AbstractA formal expansion of the CRM in powers of a small parameter is presented. The terms of the expansion are products of matrices. Inverses are interpreted as effects of cascades.It will be shown that this allows for the separation of the different contributions to the populations, thus providing a natural classification scheme for processes involving atoms in plasmas. Sum rules can be formulated, allowing the population of the levels, in some simple cases, to be related in a transparent way to the quantum numbers.

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