Probing electron transfer dynamics at MgO surfaces by Mg-atom desorption.
Ultraviolet excitation of high surface area MgO films using 4.7 eV femtosecond pulses results in neutral Mg-atom desorption with hyperthermal kinetic energies in the range 0.1-0.4 eV. The Mg-atom hyperthermal energies and power dependences are similar to those previously observed using nanosecond pulsed excitation. Femtosecond two-pulse correlation measurements reveal the existence of different dynamical paths for Mg-atom desorption. One mechanism displays a sub-150 fs time scale and involves the simultaneous or near-simultaneous transition of two electrons to a 3-coordinated Mg(2+) site. Other paths display picosecond time scales that we associate with dynamics following electron trapping at 3-coordinated Mg(2+) surface sites.
Joly
Alan G
AG
Pacific Northwest National Laboratory, P.O. Box 999, Richland, WA 99352, USA.
Henyk
Matthias
M
Beck
Kenneth M
KM
Trevisanutto
Paolo E
PE
Sushko
Peter V
PV
Hess
Wayne P
WP
Shluger
Alexander L
AL
D000327:Adsorption; D002627:Chemistry, Physical / Q000379:methods*; D004583:Electrons; D004602:Elements; D007700:Kinetics; D007834:Lasers; D008027:Light; D008274:Magnesium / Q000737:chemistry*; D008277:Magnesium Oxide / Q000737:chemistry*; D008854:Microscopy, Electron; D046529:Microscopy, Electron, Transmission; D008956:Models, Chemical; D010777:Photochemistry / Q000379:methods; D013499:Surface Properties; D013997:Time Factors
D004602:Elements; D008277:Magnesium Oxide; D008274:Magnesium