A Full Multiple Scattering Model for the Analysis of Time-Resolved X-ray Difference Absorption Spectra.

A full multiple theoretical model (MXAN) is applied to fit picosecond difference X-ray absorption spectra at the ruthenium L3edge upon photoexcitation of aqueous RuII(bpy)32. We show that fitting difference spectra allows an increase in sensitivity, such that slight structural changes can be retrieved, which are not detected in fitting full spectra. The Ru−N bond distances of the excited complex in the 3MLCT state are in good agreement with recently published values. The implementation of the present approach to L-edge spectra and its high sensitivity opens opportunities for its extension to a large class of experiments where difference X-ray absorption spectra are recorded. [ABSTRACT FROM AUTHOR]