Highly rotationally excited states of floppy molecules: H2D+withJ⩽ 20

Abstract

A partitioning of the generalized triatomic hamiltonian of the preceding paper is developed which allows the calculation of highly-excited rotational states, without approximation, in a two-step variational procedure. Iterative diagonalization techniques are found to be particularly useful for the second variational step. The rotationally-excited states of H₂D⁺ are studied with J ⩽ 20, well into the region where the ground and excited state manifolds overlap. Comparison of results for two different ab initio potentials and convergence considerations suggest that pure rotational transition frequencies obtained from our results should be accurate to about 1 cm^-1 for J ∼ 15.