RG-2) (RG = HE, NE, AR) INTERACTIONS - AB-INITIO POTENTIALS AND COLLISION PROPERTIES(CL(P)

The lowest states of Sigma and Pi symmetry of Rg ... Cl (Rg=He, Ne, Ar ) complexes were investigated using the coupled cluster approach with single, double, and noniterative triple excitations (CCSD(T)) in an ex tended basis set including band functions. The Sigma states possess de eper minima at shorter interatomic distances than the corresponding Pi states. The Sigma-Pi splittings, which for He ... Cl and Ar ... Cl ar e significantly larger than previously deduced, are mainly due to diff erences in the exchange repulsion terms. The total energies were disse cted into electrostatic, exchange, induction, and dispersion component s. The calculated potentials have been used in the calculations of col lision properties of Rg ... Cl systems. Absolute total cross sections, spin-orbit quenching rate constants, and diffusion coefficients were evaluated from both the nb initio and previously available empirical p otentials. The performance of ab initio potentials in these calculatio ns proved to be very reasonable. (C) 1998 American Institute of Physic s.