CCSD(T) potential energy surface and bound rovibrational level calculations for the Ar–ICl(X) complex

The intermolecular potential between Ar atom and ICl fixed at its equilibrium is determined by CCSD(T) calculations. We used effective-core potentials for iodine, augmented correlation consistent basis sets (aug-cc-pVnZ, n=T,Q) for Cl and Ar atoms with an additional set of bond functions. The global potential minimum corresponds to the linear Ar–I–Cl structure with well-depth De=328.1 cm−1, r(Ar⋯I)=3.555 Å and ks=3.45 N m−1, in accord with the one determined by the experiment with r(Ar⋯I)=3.576 Å and ks=3.20 N m−1. Bound state calculations are carried out for J=0 and 1 rotational states. Accordingly, the lowest level corresponds to linear Ar–I–Cl isomers, while stable isomers are also found for T-shaped and antilinear species.