Description
Charge-transfer-to-solvent (CTTS) excitations in aqueous solution provide a prototypical route to excess-electron formation in liquids. The generation of low-energy electrons is a key step in radiation chemistry and radiation-induced damage, yet the earliest stages of CTTS-state formation remain poorly understood. In particular, it is still unclear whether the initially prepared states are best described as discrete, weakly bound solvent-supported resonances or as states already strongly mixed with delocalized solvent electronic configurations.
Advanced X-ray spectroscopies, in particular resonant Auger electron spectroscopy (RAES) and resonant inelastic X-ray scattering (RIXS), offer a unique route of probing the nascent features of the CTTS process. In combination with ab initio calculations, these methods make it possible to access the electronic structure and spectroscopic response prior to significant solvent reorganization, and to identify signatures of the transition from localized, solvent-supported CTTS resonances to intrinsically delocalized electronic states. I will show how this framework can be used to describe CTTS-state formation across a broad range of systems, from simple solvated ions such as Na+,Mg2+,and Al3+$^1$, to more biologically relevant molecules including amino acids such as cysteine and even DNA-related systems.
