QUENCHING OF THE DISSOCIATIVE ELECTRON-ATTACHMENT RESONANCES OF O2 PHYSISORBED ON AMORPHOUS ICE

Measurements of electron stimulated desorption (ESD) yields of O-, at incident electron energies below 20 eV, from 0.15 monolayers (ML) of O 2 physisorbed at 20 K on a variety of molecular solids have been perfo rmed. It is observed that for O2 condensed on 4 ML of H2O, the O- sign al from dissociative electron attachment (DEA) to O2 is entirely absen t. We attribute this to a complete quenching of the dissociative 2PI(u ), 2SIGMA(g)+, and 2SIGMA(u)+, resonances of O2- by the adjacent water molecules.