AB INTIO POTENTIAL ENERGY SURFACE AND EIGENVALUES OF $A^{2}\Delta$ STATE OF $ArCH^{a}$

$^{a}$ Work supported by National Science FoundationAuthor Institution: Department of Chemistry, Emory UniversityRotationally resolved spectra of A-X transition of ArCH/D van der Waals complex have been reported previously and 7 bands were tentatively assigned. In order to make more definite assignments high level ab initio calculations have been performed. 2-D interaction potential for $CH(A)-Ar$ (with CH bond fixed at $r_{c}=1.102{\AA}$ for $A^{2}\Delta$) was calculated with MRSDCI method including Davidson and counterpoise correction. The basis set was Dunning's correlation-consistent vqz with diffuse s and p orbitals. The potential surface exhibits two minima, linear $Ar\ldots H-C$. and $Ar\ldots C-H$ whose respective well depths are $85 cm^{-1}$ and $60 cm^{-1}$. The potential anisotropy is dominated by dipole and quadrupole terms on CH. Bound ro-vibrational eigentates were calculated for various J values and compared with experimental results