A comparative theoretical study of the C2 v and C3 v reaction of H 2 with a Pt 4 cluster

Abstract

The C 2 v and C 3 v interaction of a platinum pyramidal tetramer with the hydrogen molecule study was carried out by means of ab initio multiconfigurational self consistent field plus variational and multireference second-order Möller–Plesset perturbational configuration interaction (CIPSI) calculations, using relativistic effective core potentials. The Pt 4–H 2 interactions were studied for the possible approaches of H 2 in C 2 v and C 3 v symmetries. The lowest five electronic states X 3T 1, a 1T 1, a 1A 1, a 3A 1 and b 1A 1 of the bare cluster were considered to study these interactions. In the C 2 v case, the Pt 4 pyramid cluster in theirs lowest three electronic states X 3B 2 (X 3T 1), a 1B 2 (a 1T 1), a 1A 1 (a 1A 1) is able of capturing and breaking the hydrogen molecule, only by the C 2 v H 2 edge-on perpendicular approach after surmounting theirs respective energy barriers. In the C 3 v case, the Pt 4 pyramid cluster in theirs lowest three electronic states X 3E (X 3T 1), a 1E (a 1T 1), a 1A 1 (a 1A 1) captures and breaks the hydrogen molecule by the face-on approach after surmounting theirs respective energy barriers. Meanwhile, by its vertex-on approach this cluster only can capture the H 2 molecule. The results obtained here for the Pt 4–H 2 C 2 v and C 3 v interaction are discussed and compared with previous C s–H 2 interaction approach to a Pt 4 cluster study.