Spectroscopy of HD+ in high angular momentum states

Abstract We present measurements and calculations of infrared transitions between highly rotationally excited states of HD + . Some of the states involved are rotationally quasibound levels lying up to 2300 cm −1 above the lowest dissociation limit, H + +D(1s). The transitions to quasibound levels were located using new ab initio artificial channels scattering theory calculations, and recorded by monitoring the fragments produced by rotational predissociation through the centrifugal barrier. The bound to bound transitions were recorded by monitoring fragments produced by photodissociation. Experimental measurements of absolute transition wavenumbers are found to be in excellent agreement with the theoretical predictions. Predissociation linewidths were also measured and are compared with theoretical calculations.