Inverse Velocity Dependence of Vibrationally Promoted Electron Emission from a Metal Surface

• DOI: 10.1126/science.1160040
• Publication Date: 2008-09-02T20:24:36Z
• Authors: N. H. Nahler; J. D. White; J. LaRue; D. J. Auerbach; A. M. Wodtke
• Keywords: Biological and Chemical Physics; electron emission; cesium; Other Chemistry; nonadiabatic electronic effect; Physical Chemistry; 01 natural sciences; metal surfaces; molecular interactions; 0104 chemical sciences

All previous experimental and theoretical studies of molecular interactions at metal surfaces show that electronically nonadiabatic influences increase with velocity. We report the observation a electronic effect follows opposite trend: The probability electron emission from low–work function surface—Au(111) capped by half monolayer Cs—increases as velocity incident NO molecule decreases during collisions highly vibrationally excited NO(X 2 π ½ , V = 18; is vibrational quantum number NO), reaching 0.1 lowest studied. these results are consistent autodetachment mechanism, whereby possible only beyond certain critical distance surface. This outcome implies important energy-dissipation pathways involving excitations and, furthermore, not captured present methods may influence reaction rates surfaces.