Publication Date:
2008-08-30
Description:
All previous experimental and theoretical studies of molecular interactions at metal surfaces show that electronically nonadiabatic influences increase with molecular velocity. We report the observation of a nonadiabatic electronic effect that follows the opposite trend: The probability of electron emission from a low-work function surface--Au(111) capped by half a monolayer of Cs--increases as the velocity of the incident NO molecule decreases during collisions with highly vibrationally excited NO(X(2)pi((1/2)), V = 18; V is the vibrational quantum number of NO), reaching 0.1 at the lowest velocity studied. We show that these results are consistent with a vibrational autodetachment mechanism, whereby electron emission is possible only beyond a certain critical distance from the surface. This outcome implies that important energy-dissipation pathways involving nonadiabatic electronic excitations and, furthermore, not captured by present theoretical methods may influence reaction rates at surfaces.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Nahler, N H -- White, J D -- Larue, J -- Auerbach, D J -- Wodtke, A M -- New York, N.Y. -- Science. 2008 Aug 29;321(5893):1191-4. doi: 10.1126/science.1160040.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, CA 93106-9510, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/18755972" target="_blank"〉PubMed〈/a〉
Print ISSN:
0036-8075
Electronic ISSN:
1095-9203
Topics:
Biology
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Chemistry and Pharmacology
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Computer Science
,
Medicine
,
Natural Sciences in General
,
Physics
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