1 1 UV photodissociation and photodesorption of N2O on Ag(111)

Abstract. Nanosecond laser induced photoreactions of N2O adsorbed on Ag(111) have been studied by temperature programmed desorption (TPD) and mass-selected, angle-dependent time-of-flight (MS-TOF) measurements of neutral desorbing particles. N2O molecules in the first monolayer are thermally inert but photodissociate into N2 + O, or photodesorb molecularly or dissociatively, at photon energies above 3.5 eV. We have found that TOF spectra of photodesorbed N2 as well as of N2O measured at hν = 4.7 eV consist of two velocity components. The desorption flux of the fastest component of N2O is peaked ~25 ° off the surface normal, whereas the others are directed in the surface normal. Origins and photoexcitation as well as photodesorption mechanisms of the N2O and N2 signals are discussed