On the application of Canonical Perturbation Theory up to the dissociation threshold

Abstract

We investigate a model system consisting of a Morse oscillator strongly coupled to a doubly-degenerate bending degree of freedom and show that Canonical Perturbation Theory is able to provide a fairly precise, though not exact, approximation of the Hamiltonian up to the dissociation threshold. Quantum mechanical results and classical ones are discussed in this Letter.