Following Metal-to-Ligand Charge-Transfer Dynamics with Ligand and Spin Specificity Using Femtosecond Resonant Inelastic X-ray Scattering at the Nitrogen K-Edge
Raphael M. Jay, Sebastian Eckert, Benjamin E. Van Kuiken, Miguel Ochmann, Markus Hantschmann, Amy A. Cordones, Hana Cho, Kiryong Hong, Rory Ma, Jae Hyuk Lee, Georgi L. Dakovski, Joshua J. Turner, Michael P. Minitti, Wilson Quevedo, Annette Pietzsch, Martin Beye, Tae Kyu Kim, R. W. Schoenlein, Philippe Wernet, Alexander Föhlisch, Nils Huse
Abstract
how femtosecond resonant inelastic X-ray scattering (RIXS) at the ligand K-edge allows one to uniquely probe changes in the valence electronic structure following a metal-to-ligand charge-transfer (MLCT) excitation. Metal-ligand hybridization is probed by nitrogen-1s resonances providing information on both the electron-accepting ligand in the MLCT state and the hole density of the metal center. By comparing to spectrum calculations based on density functional theory, we are able to distinguish the electronic structure of the electron-accepting ligand and the other ligands and determine a temporal upper limit of (250 ± 40) fs for electron localization following the charge-transfer excitation. The spin of the localized electron is deduced from the selection rules of the RIXS process establishing new experimental capabilities for probing transient charge and spin densities.