Negative-ion resonances in vibrational excitation and photochemistry of chemisorbed molecules: a critical case study of O2/Pt(111)

Abstract

We have conducted an extensive and critical high-resolution electron energy-loss spectroscopy (HREELS) analysis of negative-ion resonances in O₂/Pt(111). Such resonances have been suggested to play an important role in the photochemistry of molecular oxygen on transition metals. The scattered electron intensity has been recorded as a function of both primary electron energy and final scattering angle. We find a pronounced feature located less than 1 eV above the vacuum level, and discuss general trends in the location of the σ* resonance and its role in hot-electron-driven surface photochemistry.