title: Experimental requirements for light-induced reactions in powders investigated by time-resolved X-ray diffraction.
abstract: A general outline of how to perform a light-excited time-resolved diffraction experiment by applying the optical pump/X-ray probe technique is given. Owing to the difference in penetration depths between the optical light (laser) pump and the X-ray probe, only specific or specially designed crystalline systems can be investigated, so special requirements have to be fulfilled concerning the sample and its compartments. A summary of the experimental conditions of optical pump/X-ray probe experiments is presented, emphasizing why the use of powder diffraction is a useful and necessary X-ray technique for this kind of experiment. The possibilities and bottlenecks of time-resolved X-ray diffraction on the picosecond time scale will be demonstrated in the powder diffraction studies of N,N-dimethylaminobenzonitrile and N,N-diisopropylaminobenzonitrile, where the photo-induced structural changes of these molecular organic systems have been studied as a function of time.
authors.affiliation: Max-Planck-Institut für Biophysikalische Chemie, Abteilung Spektroskopie und Photochemische Kinetik, Am Fassberg 11, 37077 Göttingen, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Davaasambuu
authors.forename: P
authors.initials: P
authors.lastname: Durand
authors.forename: S
authors.initials: S
authors.lastname: Techert
mesh_terms: D016477:Artifacts; D007700:Kinetics; D008027:Light; D008968:Molecular Conformation; D009570:Nitriles / Q000032:analysis / Q000737:chemistry / Q000528:radiation effects; D010777:Photochemistry / Q000379:methods*; D011208:Powders / Q000032:analysis / Q000737:chemistry* / Q000528:radiation effects*; D012107:Research Design; D013048:Specimen Handling / Q000379:methods*; D014961:X-Ray Diffraction / Q000379:methods*
chemical_list: D009570:Nitriles; D011208:Powders; C014356:benzonitrile