Time-resolved photoelectron spectroscopy of bulk liquids at ultra-low kinetic energy

Time-resolved photoelectron spectroscopy (TR-PES) of ultrafast dynamics in solution is presented. To measure the photoelectron kinetic energy distribution (PKED) that is free from inelastic scattering in solution, photoelectrons were generated with ultra-low kinetic energies (ULKE: <5 eV). Time constants of the elementary processes in the charge-transfer-to-solvent (CTTS) reaction from I to bulk water were in excellent agreement with those obtained by transient absorption spectroscopy, demonstrating the bulk-sensitivity of TR-PES-ULKE. The analysis suggests that the CTTS reaction proceeds via two intermediates, and that 30% of the first intermediate and 70% of the second intermediate respectively are quenched by geminate recombination between the electron and the neutral iodine atom. (C) 2010 Elsevier B.V. All rights reserved.