Seminars Archive

Electron Dynamics in Aqueous Solution Probed via Resonant Auger-Electron Spectroscopy

Abstract
Charge-transfer-to-solvent (CTTS) excited states of aqueous chloride and hydroxide solution are studied by a novel experimental approach based on resonant inner-shell photoexcitation, which relates to a series of excitations to lowest and higher CTTS states. These states are clearly identified through the occurrence of characteristic spectator Auger decays to double Cl 3p valence-hole states. Both experiment and theory show that CTTS states are more stabilized and are more definitely visible than those in single Cl 2paq- core excitations and in optical valence excitations. In aqueous hydroxide solution, different behavior is observed. Here, ultrafast intermolecular energy transfer ha is observed as a new autoionization mechanism. This is the first time that such a process is reported in a hydrogen-bonded system. The key to perform photo- and Auger-electron spectroscopy studies from aqueous solutions is the use of a liquid microjet in ultrahigh vacuum in conjunction with synchrotron radiation.