Bound atomndash;diatomic molecule complexes. Anisotropic intermolecular potentials for the hydrogenndash;rare gas systems

摘要

Spectra of the van der Waals complexes H2ndash;Ar, Kr, Xe, and D2ndash;Ne have been analyzed to obtain anisotropic intermolecular potentials and transition dipole moments. The Morsehyphen;splinendash;van der Waals functional form is used to describe the potentials. Eigenvalues were computed by solving the close coupling equations, and calculated transition frequencies were fit to the experimentalQ1(0) andS1(0) peak frequencies by a least squares technique. For this purpose experimental peaks were chosen from thePandRas well as theNandTbranches of the spectra. The absorption was computed for each transition. The total absorption contour for a spectrum was obtained by assuming a Lorentzian line shape for the individual transitions and summing contributions from overlapping lines. The agreement between calculated and experimental absorption contours was excellent. For the Ar, Kr, and Xe complexes it was necessary to include three terms in the angular expansion of the transition dipole moment rather than the usual two terms. These three terms interfere to produce the complex absorption contours observed in some spectra. The anisotropy of the intermolecular potential was not determined completely. Rather, a linear relationship between the repulsive and attractive anisotropy coefficients is found.