This material is based on the work supported by NSF Grant No. CHE 0513163. M.Y.C. appreciates the NSF for financial support and the Vilesov’s group members for their hospitality during his stay at USC. M.Y.C. also thanks the Young Faculty Research Fund at GNU. The authors thank Professor Z. Bacic for turning their attention to the problem and for valuable discussions on the IT splitting of HCl dimers in helium.