H 2O-induced quenching of the negative-ion resonance scattering for N 2 physisorbed on Al(111)

Abstract

Monolayers of N 2 physisorbed on the Al(111) surface at 20 K, were investigated by means of high-resolution electron energy-loss spectroscopy (HREELS) and UV photoelectron spectroscopy (UPS). The N 2 stretching vibration at 290 meV is excited by negative-ion resonance scattering. By coadsorption of a 0.16 monolayer of H 2O, the N 2 stretching mode is strongly suppressed. This is explained as due to a complete quenching of the negative-ion resonance of N 2 by the H 2O molecules.