| Abstract
| - The electronic excitation of chemisorbed Cs atoms through the coherent photoinduced charge transfer fromthe Cu(111) surface turns on repulsive forces that initiate the dissociative wave packet motion. Due to unusuallyslow electronic relaxation, with the interferometric time-resolved two-photon photoemission technique it ispossible to follow the characteristic change in the surface electronic structure due to the ensuing nucleardynamics for ∼200 fs after excitation. This direct observation of the incipient bond breaking process on ametal surface provides information on a series of complex electronic and nuclear events that previously couldbe gleaned only through analysis of the reaction products. The metal band structure, the polarizability of theCs atom, and the mechanical properties of the surface strongly influence the electronic and nuclear relaxation,and therefore, the reaction efficiency. The importance of time-resolved methods in studying of surface reactionsis underscored by significant deviations in the electronic and nuclear dynamics of Cs/Cu(111) from the standardmodels for surface photochemistry.
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