Rovibrational spectra of open-shell van der Waals complexes: Ar-OH(X²)

Abstract

The infrared spectrum of Ar(¹S₀)-OH(X²) has been predicted using an ab initio potential-energy surface. We assume that the electronic spin and orbital angular momenta remain coupled to the rotational motion of the diatom in a van der Waals complex. The rovibrational energies and wave functions are calculated using a basis-set method involving expansion of the rovibrational wave function in terms of a product basis of optimized radial and angular wave functions. Unusual features are observed due to the nonzero electronic angular momentum of the diatom in the rovibrational levels. The effect of deuterium substitution on the predicted spectra has also been studied.