Knowledge Bank

Successive contact transformations are applied to the Darling-Dennison Hamiltonian expansion and the vibrational diagonalization is performed. A convenient numerical method is developed whereby resonant interactions and states can be excluded from the diagnoalization, these states subsequently being given an exact treatment. This method has been carried out to yield the diagonal and off---diagonal elements of the coefficients of angular momenta $P0$ to $P8$ to fourth order with and without excluded vibrational states. The former results are consistent with the work of $Amatetal.1$ Applications of this numerical method to the ground state and $2v2-v1-v3$ states of water will be discussed.