Zero kinetic energy electron-induced reaction of formaldehyde on Ag(111) and its significance for surface photochemistry

Abstract

Zero and low kinetic energy electrons were found to induce polymerization of submonolayer formaldehyde on Ag(111). This observation supports the mechanism that formaldehyde photochemistry on the silver surface is induced by photoexcited electrons generated in the substrate. The cross-section measured for the electron-induced polymerization is nearly constant (1 ± 0.2 × 10−15 cm2) over the electron energy range 0–20 eV. From this value, the tunneling efficiency of the photoexcited subvacuum electrons in Ag to formaldehyde on the surface is estimated to be 10−3.