AVS 52nd International Symposium
    Surface Science Monday Sessions
       Session SS-MoP

Paper SS-MoP6
"Hot Electrons" at Organic-Metal Interface: Photodissociation of Phenol on Ag(111)

Monday, October 31, 2005, 5:00 pm, Room Exhibit Hall C&D

Session: Surface Science Poster Session
Presenter: S. Ryu, Seoul National University, Korea
Authors: S. Ryu, Seoul National University, Korea
J. Chang, Seoul National University, Korea
S.K. Kim, Seoul National University, Korea
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Photodissociation of many organic adsorbates on metal surfaces has been attributed to photoexcited "hot electrons". To address this issue, we have explored the interfacial electronic structure of phenol adsorbed on Ag(111) using time-resolved two-photon photoemission spectroscopy. The photoinduced anion state of phenol was found at 3.1 eV above the Fermi level at one monolayer coverage. The binding energy of this state remained constant at around 0.7 ~ 0.8 eV for all coverages. Polarization dependence of the photoelectron signal revealed mechanistic details for each excitation step. The lifetime of the anion state was found to increase from 33 to 60 fs, indicating its lesser coupling to the bulk as the coverage increased from 1 to 9 ML. These findings demonstrate the role of hot electrons in photodissociation of adsorbates.