Structural dynamics and electronic structure changes probed with lasers and X-rays

Several new results and opportunities for ultrafast x-ray absorption spectroscopy (XAS) are demonstrated. It is possible to work with highly dil. solns. in transmission mode without dramatic loss of signal-to-noise ratio. This is very promising as one can envision the study of samples, for which large concns. are impossible to reach. Moreover, it is possible to scan the time delay between the laser pump pulse and the x-ray probe pulse, and therefore follow the evolution of the system from the start. The operation of an optical x-ray cross-correlator is also demonstrated. The time resoln. is not a limiting factor and the expts. are feasible with sources of shorter x-ray pulses, provided the flux is not too low. [on SciFinder (R)]