Oxidation of the Mo(100) Surface at Room Temperature Studied by Infrared Spectroscopy

The reflection-absorption spectrum of a saturation coverage of oxygen on Mo(100) at room temperature displays a weak and broad band centered around 780cm-1 and a stronger and sharper band at 1015cm-1. The latter is correlated with the appearance of a 1x1 LEED pattern with high background. Based on the work of Bauer and Poppa(1) and Fryberger and Stair;(2) we conclude that this mode corresponds to molydenum oxide with the oxygen adsorbed on an on-top site, similarly to the O/W(100) system.(3) Between 1.0 and 1.4 monolayers, this mode shifts from 985 to 1015cm-1, which is consistent with the development of a uniform oxygen layer.