X‐ray Absorption Spectroscopy for the Characterization of Photoinduced Linkage Isomers in Single Crystals: Experimental Setup and XANES Results**

摘要

Abstract Photoinduced linkage isomers (PLI) of the nitrosyl ligand in single crystals of Na2[Fe(CN)5NO] ⋅ 2H2O (SNP, sodium nitroprusside) have been studied by X‐ray absorption spectroscopy (XAS) at low temperatures, using a cryostat allowing in‐situ polarized LASER irradiation and XAS measurements. In the XANES (X‐ray absorption near edge structure) region a significant modification of the pre‐edge peak intensities is observed after irradiation of the ground state (GS) nitrosyl NO‐κN isomer with light in the blue and infrared spectral range, used for the generation of the isonitrosyl NO‐κO isomer (MS1) and the side‐on bound κ2N,O isomer (MS2), respectively. These observations are interpreted with respect to the changes in the nature of the frontier (unoccupied) molecular orbitals of the different linkage isomer configurations, expected from earlier calculations.