Molecular Physics seminar

Energy Transfer at Metal Surfaces beyond the Born-Oppenheimer Approximation

by Prof. Alec Wodtke (MPI for Biophysical Chemistry, Göttingen (DE))

FA31 ()


Interactions of molecules at metal surfaces can result in energy exchange with the electrons of the metal [1]. This complicates theoretical strategies designed to simulate surface reactivity, most of which today are based on the Born-Oppenheimer approximation [2]. This talk describes experiments on energy transfer between small molecules and simple, well-ordered surfaces, especially single crystal metal surfaces. A new project designed to discover the detailed picture by which atoms and molecules stick to metal surfaces will be described. In particular, to what extent are electronic excitations necessary to facilitate sticking. In the course of designing this project, which relies on a photochemical atomic beam source, it became clear that one can produce ultra-fast (40 ps) H-atom pulses. This concept will be described in detail. Studies of X-ray photodissociation of small molecules will provide basic information for extending this concept, potentially to the sub-ps time regime. [1] Wodtke, A.M., D. Matsiev, and D.J. Auerbach, Prog. Surf. Sci., 2008. 83(3): 167-214. [2] Born, M. and R. Oppenheimer, Ann. Phys.-Berlin, 1927. 84(20): 0457-0484.