PNNL

Abstract

We report the first experimentally realized ultrafast two-color X-ray pump X-ray probe transient absorption experiment performed in solution. A fs X-ray pump pulse creates a localized excitation by removing a 1s electron from an Fe atom in solvated ferro- and ferricyanide complexes. Following the ensuing Auger–Meitner cascade, the second X-ray pulse probes the Fe 24 1s?3p transitions in resultant novel core-excited electronic states. Careful comparison of the experimental spectra with theory provides new insight into correlated interactions of valence 3d with 3p and deeper lying electrons. Such information is essential for accurate modelling and predictive synthesis of transition metal complexes relevant for applications ranging from catalysis to information storage technology. This study demonstrates the experimental realization of the scientific opportunities possible with the continued development of multicolor multi-pulse X-ray spectroscopy in complex condensed phase systems.