Liu Zhiheng, Feldman L C, Tolk N H, Zhang Zhenyu, Cohen P I
Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN 55455, USA.
Science. 2006 May 19;312(5776):1024-6. doi: 10.1126/science.1124529.
Past efforts to achieve selective bond scission by vibrational excitation have been thwarted by energy thermalization. Here we report resonant photodesorption of hydrogen from a Si(111) surface using tunable infrared radiation. The wavelength dependence of the desorption yield peaks at 0.26 electron volt: the energy of the Si-H vibrational stretch mode. The desorption yield is quadratic in the infrared intensity. A strong H/D isotope effect rules out thermal desorption mechanisms, and electronic effects are not applicable in this low-energy regime. A molecular mechanism accounting for the desorption event remains elusive.
过去通过振动激发实现选择性键断裂的努力因能量热化而受阻。在此，我们报告了利用可调谐红外辐射从Si(111)表面进行氢的共振光解吸。解吸产率的波长依赖性在0.26电子伏特处出现峰值：这是Si-H振动拉伸模式的能量。解吸产率与红外强度呈二次方关系。强烈的H/D同位素效应排除了热解吸机制，并且电子效应在这种低能量状态下并不适用。解释该解吸事件的分子机制仍然难以捉摸。
