Rovibrational spectra of open-shell van der Waals complexes: H2–OH (X 2Π)

A variational basis function approach is described for the calculation of the rovibrational bound states and infrared spectrum of a van der Waals complex of a closed-shell diatom and a 2Π diatom using no angular momentum decoupling approximations. Using an ab initio potential surface, the method is then applied to calculate the bound states and spectra of the system H2–OH (X 2Π), and results are given for the complex containing both para and ortho H2. Interesting similarities and differences are discovered on comparing the results with those for the related Ar–OH and H2–HF complexes.