Energy Levels and Thermodynamic Functions for Molecules with Internal Rotation. III. Compound Rotation

Abstract

A method is given for calculating the elements of the kinetic energy matrix for rotation for any molecule. The treatment includes the effects due to any number of linked rotating groups, balanced or unbalanced. In a simple case these equations reduce to the simpler ones of the two previous papers of this series. This rotational matrix is then converted into the matrix of the internal rotations. The reduced moments of inertia that form the latter are then used with the methods of the previous papers of this series to calculate energy levels and thermodynamic functions.

Computed Rate Coefficients and Product Yields for c-C5H5 + CH3 → Products

“…The reduced moment of inertia based on the equilibrium geometry was calculated using the formulas described by Pitzer. [24][25][26] In this paper we have used the reduced moment of inertia I (2,3) , 27 and the one dimensional Schroedinger equation was solved numerically. For cyclopentadienyl an additional moment of inertia for pseudo rotation was used as described in Section 3.1.…”

Thermodynamics of Anharmonic Systems: Uncoupled Mode Approximations for Molecules

“…However, under the assumption of uncoupled modes, the reduced moments of inertia can be approximated with the diagonal elements of the internal rotation kinetic energy matrix, which can be derived by the procedures reported by Kilpatrick and Pitzer. 47 The coefficients of Eq. (11) can be determined by restricting to pass through the i th and (i-1) st data points…”

Theoretical study of the OH-initiated atmospheric oxidation mechanism of perfluoro methyl vinyl ether, CF3OCFCF2

“…Reduced moments of inertia are obtained following the method by Kilpatrick and Pitzer. 22 Lennard-Jones collision parameters of the adducts are estimated as s = 6.5 Å, e = 360 K, with an average DE down = B300 cm À1 in the exponential-down energy transfer model, with air as a bath gas; some variations of DE down were examined (see below). The level of theory employed here is intended mainly to provide a semiquantitative view of the reaction kinetics.…”