CONSERVATION OF ANGULAR-MOMENTUM IN RRKM THEORY - A 3-DIMENSIONAL MODEL FOR NONLINEAR MOLECULES

The ''usual'' implementation of the unimolecular rate constant in RRKM theory treats nonlinear molecules as pseudo-diatomics and thus does n ot conserve total angular momentum. A three-dimensional model for cons ervation of total angular momentum for vibrator transition states with the K rotational quantum number either active or adiabatic is present ed and a comparison made between this model and the ''usual'' one in t he low-pressure limit for two different reactions. This showed that th e three-dimensional model resulted in significantly larger rate consta nts when the K rotor was active, indicating the importance of conserva tion of total angular momentum.