TY - JOUR
T1 - Time-resolved synchrotron diffraction and theoretical studies of very short-lived photo-induced molecular species
AU - Coppens, Philip
AU - Benedict, Jason
AU - Messerschmidt, Marc
AU - Novozhilova, Irina
AU - Graber, Tim
AU - Chen, Yu Sheng
AU - Vorontsov, Ivan
AU - Scheins, Stephan
AU - Zheng, Shao Liang
PY - 2010
Y1 - 2010
N2 - Definitive experimental results on the geometry of fleeting species are at the time of writing still limited to monochromatic data collection, but methods for modifications of the polychromatic Laue data to increase their accuracy and their suitability for pump-probe experiments have been implemented and are reviewed. In the monochromatic experiments summarized, excited-state conversion percentages are small when neat crystals are used, but are higher when photoactive species are embedded in an inert framework in supramolecular crystals. With polychromatic techniques and increasing source brightness, smaller samples down to tenths of a micrometre or less can be used, increasing homogeneity of exposure and the fractional population of the excited species. Experiments described include a series of transition metal complexes and a fully organic example involving excimer formation. In the final section, experimental findings are compared with those from theoretical calculations on the isolated species. Qualitative agreement is generally obtained, but the theoretical results are strongly dependent on the details of the calculation, indicating the need for further systematic analysis.
AB - Definitive experimental results on the geometry of fleeting species are at the time of writing still limited to monochromatic data collection, but methods for modifications of the polychromatic Laue data to increase their accuracy and their suitability for pump-probe experiments have been implemented and are reviewed. In the monochromatic experiments summarized, excited-state conversion percentages are small when neat crystals are used, but are higher when photoactive species are embedded in an inert framework in supramolecular crystals. With polychromatic techniques and increasing source brightness, smaller samples down to tenths of a micrometre or less can be used, increasing homogeneity of exposure and the fractional population of the excited species. Experiments described include a series of transition metal complexes and a fully organic example involving excimer formation. In the final section, experimental findings are compared with those from theoretical calculations on the isolated species. Qualitative agreement is generally obtained, but the theoretical results are strongly dependent on the details of the calculation, indicating the need for further systematic analysis.
KW - Dynamical structural science
KW - Excimers
KW - Excited-state molecular geometries
KW - Pump-probe experiments
KW - Time-resolved diffraction
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U2 - 10.1107/S0108767309055342
DO - 10.1107/S0108767309055342
M3 - Article
C2 - 20164641
AN - SCOPUS:77249083260
SN - 0108-7673
VL - 66
SP - 179
EP - 188
JO - Acta Crystallographica Section A: Foundations of Crystallography
JF - Acta Crystallographica Section A: Foundations of Crystallography
IS - 2
ER -