Theoretical study of the He-HCN, Ne-HCN, Ar-HCN, and Kr-HCN complexes

The two-dimensional potential energy surfaces for the He-HCN, Ne-HCN, Ar-HC N, and Kr-HCN complexes are presented. Calculations have been performed usi ng single and double excitation coupled-cluster theory with noniterative tr eatment of triple excitations [CCSD(T)] and the augmented correlation-consi stent polarized triple-zeta basis set (aug-cc-pVTZ) with an additional (3s3 p2d2f1g) set of bond functions. The potentials have been used to find the v ibration-rotation energies of the four complexes and their deuterated analo gs. The frequencies of rotational or rovibrational transitions found for He -HCN and Ar-HCN are in very good agreement with the experimental results. G ood agreement is also obtained with the experimental rotational transition frequencies for Kr-HCN. For Ne-HCN, on the other hand, the agreement with t he experimental data is not as good, but can be improved by using larger ba sis sets. (C) 2001 American Institute of Physics.