Crystallographic investigation of transient states by time-resolved techniques using synchrotron radiation

The three-dimensional structure of short-lived excited or transient states in molecules may be investigated by means of time-resolved X-ray diffraction on time scales > 100 ps using the high intensity and pulsed time structure of synchrotron radiation. The experimental techniques, which may involve crystal cooling to low temperatures, and results of first applications to studies of laser-excited states with a time resolution between 10 ns and 500 μs are described.On peut étudier la structure de molécules dans des états excités de courte durée de vie ou dans des états transitoires, au moyen de la diffraction des rayons X sur une échelle de temps supérieure à 100 ps grâce à la forte intensité et au caractère pulsé du rayonnement synchrotron. On décrit les techniques expérimentales, qui peuvent utiliser les techniques cryogéniques, et les résultats d'étude d'états excités par laser avec une résolution temporelle comprise entre 10 ns et 500 μs

REAL-TIME REDUCTION OF AREA DETECTOR DATA BY HARDWARE (DACOM) FOR STATIC AND TIME-RESOLVED CRYSTALLOGRAPHY

A data handling system ("DACOM") has been developed for high counting rate (of, at present, 1 MHz and eventually 10 MHz) diffraction data collection with quantum counting or integrating area detectors using synchrotron radiation and for on-line data evaluation in real time. DACOM data handling is done by hardware including look-up tables programmed on the basis of pattern prediction. DACOM may be applied in protein crystallography, both in static studies involving very short exposure and overall measuring times, and in (usec to msec) time-resolved data collection. Results of a test application are described

Entwicklung resonanter Roentgenbeugungsmethoden zur Analyse der Struktur von Proteinen

Available from TIB Hannover: DtF QN1(69,54) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany)DEGerman