Manifestations of the effects of nonrigidity of molecules in the thermodynamic and transport characteristics of water vapor

The influence of bending-rotation excitation of H₂O on the thermodynamic and transport characteristics of water vapor was quantitatively analyzed. The second virial coefficient, the self-diffusion coefficients of excited H₂O molecules, and the diffusion coefficients of these molecules in polar and nonpolar gases were considered. Substantial changes in the dipole moment of molecules caused by bending-rotation excitations were shown to seriously affect these characteristics in certain instances. An effective method for averaging the kinetic collision integrals over polar molecule orientations was suggested. The averaged integrals were determined in a wide range of variations of the parameter characterizing dipole-dipole interactions of molecules.