A Full-Dimensional Quantum Dynamical Study of the Vibrational Ground State of H3O2 – and its Isotopomers

Abstract

Abstract We investigated the effect of deuteration on the vibrational ground state of the hydrated hydroxide anion using a nine-dimensional quantum dynamical model for the case of J = 0. The propagation of the nuclear wave function has been performed with the multi-configuration time-dependent Hartree method which yielded zero-point energies for the normal and fully deuterated species in quantitative agreement with previous diffusion Monte Carlo calculations. According to the zero-point energy the isotopomers having the hydrogen atom in the bridging position are more stable by about 1 kJ/mol as compared to the deuterium case. This holds irrespective of the deuteration state of the two OH groups. We also report the secondary geometric isotope effect on the O–O distance upon replacing the H- by a D-bond. It amounts to a contraction by about 0.005 Å for the symmetric isotopomers and 0.009 Å in the asymmetric case.