The dissociation process of an oxygen molecule on the Al(111) surface was investigated theoretically within the density-functional theory in terms of the spin-polarized generalized-gradient approximation and the pseudopotential method. The results have shown that the ${\mathrm{O}}_2$ molecule is attracted to the Al(111) surface and dissociates without any energy barrier, whichever configuration, the side-on or end-on configuration, the molecule is in. Comparing the potential energy surfaces of the both configurations, the end-on approach is more preferable than the side-on one. Although the electron transfer makes the total energy of the side-on configuration lower than that of the end-on one, the dissociation is expected to proceed in the original configuration, and with the abstraction at last.

• Received 27 April 1999

DOI:https://doi.org/10.1103/PhysRevB.60.7824