A multicomponent QM study of H2 dissociation on small aluminum cluster.

H-2 dissociation on small aluminum cluster, Al-2, is studied using our multicomponent quantum-mechanical (MC_QM) method, which can take account of the nuclear quantum effect (NQE) of light nucleus, such as proton and deuteron. We demonstrate that no standard density functionals can reproduce CCSD(T) geometry of van der Waals Al-2. H-2 complex well, even though the empirical dispersion correction is included. Our MC_QM calculations reveal that NQE stabilizes structures at each stationary point, and H-2 dissociation reaction is the barrierless reaction on the MC_QM effective potential energy hypersurface. The H/D isotope effect on the dissociation reaction are also analyzed. (C) 2017 The Authors. Published by Elsevier B.V.