ИСТИНА

To probe the fundamental energy exchange processes between the internal degrees of freedom in highly non-equilibrium heated medium the thermodynamic and transport proper-ties of real gases at the translation and/or electronic temperatures up to 100 000K are neces-sary. The relevant statistical calculations should apparently account for both interatomic and intramolecular (so-called non-adiabatic) interactions taking place between the constituent particles. We examined the simplified classical and semi-classical theories for multi-temperature molecular partition sums by comparing with the result of tedious quantum-mechanical calculations. Our eventual goal was to study whether the classical theory allows one to quickly calculate molecular thermodynamic and transport properties without compromising accuracy. It was numerically proved that at low temperatures the calculation should be carried out by the pure quantum method and non-adiabatic interaction must be often taken into ac-count. At high temperatures the calculation could be carried out with acceptable accuracy in the framework of classical mechanics while at intermediate temperatures (ωe~kT) a semi-classical correction is necessary to imply. The full form of the interacting-particle partition function is found to be essential to complete and correct calculation of the thermodynamic functions of the systems. The conventional statistical methods which include only the bound-state sum in the internal partition function become infeasible since it introduces discontinuities into the thermodynamic-state function at those points where the bound-state levels pass into the continuum. The work has been partially supported by the RFBR grant 11-03-00307а and 7th European framework program, grant 242311.