An analysis of O-H interaction potentials, O-H and O-D collision cross sections, and vibrational states

A detailed comparison of recently published OH, X(2)Pi, (2)Sigma(-), (4)Pi and (4)Sigma(-) potentials is carried out. These potential functions are important in the accurate determination of O-H and O-D collision cross sections. The isotope effect in the O-H and O-D cross sections plays an important role in the enhanced nonthermal escape of H and D from Mars and Venus. The quantum mechanical elastic scattering cross sections for O-H and O-D collisions are determined with a set of potentials which are constructed with a new interpolation of the short range tabulated potentials and the long range asymptotic behaviour. The important role of the asymptotic radial variation of the potential functions in the determination of the elastic cross sections is studied in detail with a semiclassical analysis, and a comparison is made with previous calculations. The vibrational energies for several different X(2)Pi bound potential functions for OH are also calculated and compared with published results. (C) 1999 Published by Elsevier Science Ltd. All rights reserved.