THE DYNAMICS OF OPEN-SHELL VANDERWAALS COMPLEXES

The theory of Van der Waals complexes formed from atoms and open-shell (SIGMA and II) diatomic molecules is developed, paying particular attention to the quantum numbers that are conserved in the complex and the angular momentum coupling cases that may be observed. Complexes formed from diatoms in multiplet SIGMA states may exhibit several different coupling schemes closely analogous to Hund's coupling cases for diatomic molecules. Complexes formed from diatoms in II states usually exhibit a coupling scheme in which the (signed) projection P of the diatom angular momentum j onto the intermolecular axis is nearly conserved. Correlation diagrams showing the bending energy levels as a function of potential anisotropy are given for complexes containing diatomic molecules in both SIGMA and II states. The transition from free internal rotor quantum numbers to near-rigid bender quantum numbers with increasing anisotropy is investigated. The cases of Ar-OH and Ne-OH are considered as examples.