Quantum mechanics based classical molecular dynamics study of water adsorption on (001) SrMO_3 surfaces (M = Ti, Zr)

摘要

Department of Quantum Chemistry, St. Petersburg State University, 26 Universitetsky Prospect, Peterhof, St. Petersburg 198504, Russia;Department of Quantum Chemistry, St. Petersburg State University, 26 Universitetsky Prospect, Peterhof, St. Petersburg 198504, Russia;Department of Quantum Chemistry, St. Petersburg State University, 26 Universitetsky Prospect, Peterhof, St. Petersburg 198504, Russia;%This paper reports the results of a classical molecular dynamics (CMD) study of molecular water adsorption on MO_2- and SrO-terminated SrMO_3 (001) surfaces (M = Ti, Zr) at 300 K with 1/2 ML and 1 ML coverage. Models of the force fields for the water-crystalline oxide interfaces have been proposed. These force fields describe the oxide-oxide, water-oxide and water-water interactions, as well as interactions within the water molecule itself. The water-water and flexible water intramolecular potentials have been adopted from Toukan and Rahman (Phys. Rev. B 31 (1985) 2643-2648). The results of CMD simulations of the structure of the water layers at the oxide surfaces are discussed in terms of the most probable configurations. The power spectra of the water hydrogen velocity autocorrelation functions have been calculated using the CMD trajectories. The calculated power spectra permit us to consider the vibrational modes of the different structural species formed by the water molecules at the oxide surfaces and to analyse the level of binding of these species, both between themselves and to the surface.