LASER-INDUCED DISSOCIATION OF NO2 ADSORBED ON PD(111)

UV-photodissociation of submonolayer NO2 adsorbed on top of a saturated layer of NO on Pd(111) yields desorption of NO fragments with a cross section of 3-10-18 cm2 at 6.4 eV photon energy. The wavelength dependence and the quantum state distributions demonstrate the non-thermal origin of the ejected NO fragments. A novel approach utilizing polarized light provides clear evidence that the primary process consists of an electronic excitation of the metallic substrate rather than direct absorption by the adsorbate. © 1990 Pergamon Press plc.