Fourth-Order Vibration–Rotation Hamiltonian of the Nonlinear XYX Molecule

Abstract

Detailed expressions in terms of fundamental molecular parameters are given for the fourth‐order centrifugal distortion constants of the nonlinear XYX molecule. It is shown how these expressions can be used for the determination of the cubic potential constants of the XYX molecule if they are considered in conjunction with the reduced‐Hamiltonian theory of Watson. Three reduced Hamiltonians are treated in detail, and a generalization of Watson's theory is presented, and its need is justified.