Femtosecond desorption of CO from metal surfaces:: the role of the 2π*-derived states

We critically examined femtosecond desorption of CO from various metal surfaces. We found that the energy locations of the observe 2 pi*-derived states commonly featured in all theoretical models, are too high to be effectively excited by the laser generated photoelectrons. This difficulty can be resolved if we adopt the 'Adiabatic Model' of Jennison et al. predicting the existence of short-lived antibonding states, at lower energy and can be excited by the photoelectrons, allowing desorption to occur. (C) 2001 Elsevier Science B.V. All rights reserved.