The pressure second virial coefficient of vibrating symmetric triatomic molecules

Abstract

The effect of molecular flexibility on the pressure second virial coefficient B has been evaluated for both linear molecules related to CS2 and nonlinear symmetric triatomic molecules derived from CS2. Our results show that these effects will not be significant in evaluating pairwise intermolecular potentials for these molecules. Earlier, we found this also to be the case for linear diatomic molecules. This result is different from the case of water, where much larger contributions (up to 10%) were reported by Refson et al. The dominant contribution to B is caused by molecular bond bending in both linear and nonlinear molecules and is very sensitive to the degree of nonlinearly of the molecule.