The Reduced Effective Vibration-Rotational Hamiltonian for the v(t) = 2 Levels of C(3v) Symmetric-Top Molecules

The theory of the reduction of the effective rotation-vibration Hamiltonian is applied to the v(t) = 2 states of C(3v) molecules, and the higher-order terms up to H(43) are included. The results explain clearly why it is possible to determine in this state all four spectroscopic constants eta(J), eta(K), q(12), and d(t) simultaneously without the indeterminacy problems that have been encountered in the v(t) = 1 states. Constraints suitable for most cases are proposed and alternative choices are discussed. A number of new relations among the parameters of the various reduced forms of the effective Hamiltonian is predicted. Copyright 1999 Academic Press.