What can time-resolved diffraction tell us about transient species?: excited-state structure determination at atomic resolution

The author describes his work for which he coined the word ʹphotocrystallographyʹ, a technique which consists of using a laser to pump, or excite, a molecular crystal while the X-ray diffractometer probes its structure at the atomic level. The technique is being used to study highly reactive excited molecules that exist for just millionths or even billionths of a second using very intense light sources at the National Synchrotron Light Source at Brookhaven National Laboratory and the Advanced Photon Source at Argonne National Laboratory.