Electronically Nonadiabatic Vibrational Excitation of N2 Scattered from Pt(111)

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• 作者：J枚rn Werdecker ; Pranav R. Shirhatti ; Kai Golibrzuch ; Christof Bartels ; Alec M. Wodtke ; Dan J. Harding
• 刊名：Journal of Physical Chemistry C
• 出版年：2015
• 出版时间：July 2, 2015
• 年：2015
• 卷：119
• 期：26
• 页码：14722-14727
• 全文大小：363K
• ISSN：1932-7455

文摘

Molecular beam surface scattering is used to compare vibrational excitation of N₂ molecules in collisions with clean Pt(111) and Au(111) surfaces under UHV conditions. Direct single-bounce collisions are dominant under all conditions of this work, as evidenced by narrow specular angular scattering distributions and translational incidence energy dependent rotational temperatures. N₂(v = 0 鈫?1) vibrational excitation is observed for Pt(111), but not Au(111). The excitation probabilities, ranging from 鈭?0^鈥? to 鈭?0^鈥?, follow an Arrhenius surface temperature dependence and increase with translational incidence energy with zero threshold. The observations are the typical fingerprint of nonadiabatic vibrational excitation due to an electron mediated excitation mechanism, identified in previous work on NO and CO scattering from metal surfaces. The unfavorable electron affinity of the N₂ molecule (EA = 鈭?.3 eV) makes this observation surprising and we discuss possible excitation mechanisms.