Theoretical study of the relative stabilities of H+(X)2 and H+(X)3 conformers and their clustering energies: X  CO and N2

Abstract

AbstractThird‐order Møller–Plesset perturbation theory (MP3) with a 6‐31G** basis set was applied to study the relative stabilities of H+(X)2 conformations (X  CO and N2) and their clustering energies. The effect of both basis set extensions and electron correlation is not negligible on the relative stabilities of the H+(CO)2 clusters. The most stable conformation of H+(CO)2 is found to be a C∞v structure in which a carbon atom of CO bonds to the proton of H+(CO), whereas that of H+(N2)2 is a symmetry D∞h structure. The second lowest energy conformations of H+(CO)2 and H+(N2)2 lie within 2 kcal/mol above the energies of the most stable structures. Clustering energies computed using MP3 method with the 6‐31G** basis set are in good agreement with the experimental findings of Hiraoka, Saluja, and Kebarle. The low‐lying singlet conformations of H+(X)3 (X  CO and N2) have been studied by the use of the Hartree–Fock MO method with the 6‐31G** basis set and second‐order Møller–Plesset perturbation theory with a 4‐31G basis set. The most stable structure is a T‐shaped structure in which a carbon atom of CO (or a nitrogen atom of N2) attacks the proton of the most stable conformation of H+(X)2 clusters.