Ultrafast tabletop laser-pump-x-ray probe measurement of solvated Fe(CN)6 4-.

We report on the first ultrafast laser-pump-picosecond x-ray probe measurements of solvated transition metal complexes carried out with a tabletop ultrafast laser-driven plasma x-ray source. The x-ray absorption fine structure (XAFS) spectra of Fe(CN)(6) (4-) solvated in water have been measured before and tens of picoseconds after photoexcitation with ultrashort UV laser pulses. The XAFS spectra after photoexcitation exhibits a K-edge shift indicating the increase of the iron-ligand distances. Reference spectra of Fe(CN)(6) (4-) and Fe(CN)(6) (3-) measured at a synchrotron source yield structural data that show static solvation-induced bond length changes of the metal complexes.