Supporting Information: cis to trans isomerization of azobenzene derivatives studied with transition path sampling and QM/MM molecular dynamics Anja Muzdalo, † Peter Saalfrank, ‡ Jocelyne Vreede, ¶ and Mark Santer *,† †Department of Theory and Biosystem, Max Planck Institute of Colloids and Interfaces, 14424 Potsdam, Germany ‡Department of Chemistry, University of Potsdam, 14476 Potsdam, Germany ¶Computational Chemistry, Van’t Hoff Institute for Molecular Sciences, University of Amsterdam, 1098 XH Amsterdam, The Netherlands E-mail: mark.santer@mpikg.mpg.de Phone: +49 (0)331 5679610. Fax: +49 (0)331 5679602 1 Structural parameters of AB and pp-AB from DFT/DFTB methods In Table 1 Structural parameters for AB and pp-AB from structure optimizations in vacuum are displayed for cis and trans isomers. Note the different signs appearing for PBE and DFTB3 in the listing for AB(trans ), these represent the same structure as found for B3LYP and DFTBA; the difference between DFTBA and DFTB3 for pp-AB (cis ), on the other hand, is related to the convergence towards a second minimum very close in energy. For 1