Cu titration of tilted CO on a MO

Upon CO exposure to a Mo( 110) surface at 95 K, the initial ~0.3 monolayer (ML) of CO does not exhibit a vibrational frequency in the 1800-2200 cm-’ region, implying that the C-O axis is tilted with respect to the surface normal. Upon subsequent deposition of = 0.9 ML Cu at 95 Kfollowed by heating, infrared-reflection-adsorption-spectroscopy (IRAS) shows that a portion of the tilted CO molecules diffuses onto the Cu overlayer and assumes an upright bonding geometry, with the remainder dissociating on the MO{ 110) surface into atomic C and 0.