Dissociative adsorption of O-2 on Cu(110) and Cu(100): Three-dimensional quantum dynamics studies

The dynamics of dissociative chemisorption of oxygen on Cu(110) and Cu(100) has been studied using a time-dependent quantum wave-packet approach. Dissociation probabilities for O-2 on both (110) and (100) surfaces of copper are calculated for ground state as well as rovibrationally excited oxygen molecules. The present calculation simulates O-2 dissociation on nascent copper surfaces with no consideration for surface reconstruction. The dynamics calculation is based on a flat-surface model in which three molecular degrees of freedom are explicitly included while the lateral coordinates of the molecule are neglected. The interaction potential energy surface (PES) for the dynamics calculation is constructed using the LEPS (London-Erying-Polyni-Sato) PES form with potential parameters fitted to some available experimental and theoretical data. The barrier of the LEPS PES for oxygen dissociation on copper is 0.11 eV for Cu(110) and 0.08 eV for Cu(100). Relatively speaking, the saddle point of the O-2/Cu(110) PES is located near the entrance channel, while that of the O-2/Cu(100) is near the product channel. This feature is primarily responsible for the difference in calculated dissociation probabilities of oxygen on two surfaces. Specifically, the dissociation probability of O-2 on Cu(110) is large and less sensitive to the vibrational excitation of the molecule, while that of O-2 on Cu(100) is much smaller and more sensitive to vibrational excitation of the molecule.