Jm. Hutson et Ae. Thornley, ATOM-SPHERICAL TOP VAN-DER-WAALS COMPLEXES - A THEORETICAL-STUDY, The Journal of chemical physics, 100(4), 1994, pp. 2505-2521
The theory of the vibration-rotation states of atom-spherical top van
der Waals complexes is developed. The exact close-coupled equations ar
e closely analogous to those encountered in atom+spherical top scatter
ing. The structure of the coupled equations is investigated, and close
-coupling calculations of the bound states of Ar-CH4 are presented for
two different intermolecular potentials. The role of symmetry in the
complex is discussed, and the energy levels are interpreted using a mo
del in which the CH4 molecule undergoes hindered rotation in the field
of the Ar atom. Correlation diagrams are presented, showing how the f
ree-rotor levels are converted into near-rigid vibrational energy leve
ls as the anisotropy of the intermolecular potential increases. The ef
fect of higher-order anisotropic terms is investigated, and correlatio
n diagrams are given for complexes of tetrahedral, octahedral, and ico
sahedral molecules. The role of monomer vibrational angular momentum i
s investigated.