Photoinduced charge-transfer reactions between alkali metal clusters and hydrogen halides (HX, X = F, CL, BR) adsorbed on LiF.
Sergey Dobrin ( sdobrin-AT-chem-DOT-utoronto-DOT-ca.gif ), Javier B. Giorgi, Tae Geol Lee, Hong He, Fedor Y. Naumkin, John C. Polanyi, Sergei A. Raspopov and Jiaxi Wang
Department of Chemistry, University of Toronto, Toronto, Ontario, Canada M5S 3H6.
A sub-monolayer of atomic sodium was deposited on LiF(001) at 50 K and characterized by temperature programmed desorption, X-ray photoelectron spectroscopy, and titration with HCl. Adsorbed sodium atoms and clusters were dosed with HX, (X=F, Cl, Br) to form (HX)m ... Nan/LiF(001) (m=1 or 2), which was then irradiated by 640 or 610 nm laser-radiation to induce a charge-transfer reaction. Reaction-product atomic H(g) was observed leaving the surface, by two-color Rydberg-atom TOF spectroscopy. These H-atoms gave evidence of arising from the photoinduced harpooning reaction between the sodium clusters, Nan, on the substrate, and (HX)m adsorbed on the Nan. The translational energy distribution of H(g) gave information regarding cross-section of the harpooning event and the vibrational spacing in the radical remaining at the surface. Reaction products have been also studied by X-ray photoelectron spectroscopy and ab-initio calculations.