Equilibrium Properties of the Gas of Atoms of Which a Part is Excited within Cluster Expansion Method
A gas of atoms some of which are in excited electronic state is under consideration. Since the lifetime of an excited state is to great extent larger than the time required for establishing the equilibrium over translational degrees of freedom the system possesses equilibrium properties. They are determined essentially by many-particle resonance interactions that appear in the system of identical differently excited atoms. The present paper contains the results of numerical calculations dealing with the examination of virial state equation and density expansion for canonical pair spatial distribution function of the system in question with the accuracy up to three-particle contributions. The obtained results permit to study the excited atoms influence on gas-liquid phase transition and the excimer molecules formation in the gas with excited atoms.