APPROXIMATE DETERMINATION OF ROVIBRATIONAL DENSITIES OF STATES RHO(E,J) AND NUMBERS OF STATES W(E,J)

Compact approximate equations for rovibrational densities of states rh o(E,J) for harmonic oscillator-rigid rotor molecular systems are deriv ed. Linear molecules, spherical tops, prolate and oblate symmetric top s are considered. Vibrational densities of states are represented by t he Whitten-Rabinovitch approximation which then is convoluted with the contribution from the K-rotor (for a symmetric top). Likewise, number s of states W(E,J) are approximated for prolate symmetric top molecule s. The derived expressions allow for quick calculations of specific ra te constants k(E,J) of unimolecular reactions.