SYMMETRY-ADAPTED PERTURBATION-THEORY APPLIED TO INTERACTION-INDUCED PROPERTIES OF COLLISIONAL COMPLEXES

A symmetry-adapted perturbation theory (SAPT) is formulated for intera ction-induced electrical properties of weakly bound complexes. Asympto tic (large R) expressions are reported for the contributions to the co llision-induced dipole moments and polarizabilities up to and includin g second order in the intermolecular potential. These long-range expre ssions require knowledge only of the multipole moments and (hyper)pola rizabilities of the isolated monomers. Numerical results are given for the dipole moment of He-H-2 and the polarizability of He-2 and the ac curacy of the SAPT approach is examined by comparison with full config uration interaction results. The role of various physical contribution s to the dipole moment of He-H-2 and the polarizability of He-2 is inv estigated. The validity of the long-range approximation and the import ance of charge penetration (damping) effects are discussed.