%0 Journal Article %T Sensitivity of photoelectron diffraction to conformational changes of adsorbed molecules: Tetra-tert-butyl-azobenzene/Au(111) %+ Physik-Institut [Zürich] %+ Fachbereich Physik [Marburg] %A Schuler, A. %A Greif, M. %A Seitsonen, A. %A Mette, G. %A Castiglioni, L. %A Osterwalder, J. %A Hengsberger, M. %< avec comité de lecture %@ 2329-7778 %J Structural Dynamics %I AIP Publishing %V 4 %N 1 %P 015101 %8 2017-01 %D 2017 %R 10.1063/1.4975594 %Z Physics [physics]Journal articles %X Electron diffraction is a standard tool to investigate the atomic structure of surfaces, interfaces, and adsorbate systems. In particular, photoelectron diffraction is a promising candidate for real-time studies of structural dynamics combining the ultimate time resolution of optical pulses and the high scattering cross-sections for electrons. In view of future time-resolved experiments from molecular layers, we studied the sensitivity of photoelectron diffraction to conformational changes of only a small fraction of molecules in a monolayer adsorbed on a metallic substrate. 3,3′,5,5′-tetra-tert-butyl-azobenzene served as test case. This molecule can be switched between two isomers, trans and cis, by absorption of ultraviolet light. X-ray photoelectron diffraction patterns were recorded from tetra-tert-butyl-azobenzene/Au(111) in thermal equilibrium at room temperature and compared to patterns taken in the photostationary state obtained by exposing the surface to radiation from a high-intensity helium discharge lamp. Difference patterns were simulated by means of multiple-scattering calculations, which allowed us to determine the fraction of molecules that underwent isomerisation. %G English %L cea-04075447 %U https://cea.hal.science/cea-04075447 %~ CEA