Comment on: “The hindered rotor density-of-states interpolation function” [J. Chem. Phys. 106 , 6675 (1997)] and “The hindered rotor density- of-states” [J. Chem. Phys. 108 , 2314 (1998)]

Abstract

There has been some confusion regarding the various approximations for the hindered rotor partition function and its associated thermodynamic functions and density of states. This comment seeks to clarify the situation by comparing and contrasting the various functions, particularly with regard to the consistent use of reference energies. Only the tabular data of Pitzer and Gwinn [J. Chem. Phys. 10, 428 (1942)] and our analytic function [J. Chem. Phys. 106, 6675 (1997)] have consistent reference energies. The main contribution of our publication is the set of simple, asymptotically correct expressions for the thermodynamic functions. There are similar, but different approximations to the density of states given by Knyazev and co-workers [J. Phys. Chem. A 102, 3916 (1998)] and by me [J. Chem. Phys. 108, 1748 (1998)].