Photoelectron spectroscopy for polyatomic molecules with 22-fs time resolution

Abstract

Internal conversion (IC) in polyatomic molecules is one of the most essential processes for understanding energy transfer in photochemical reactions. The IC through conical intersection is usually very fast process, ≪100 fs time scale. Time-resolved photoelectron spectroscopy (TRPES) is one of the best methods to investigate such photochemical reaction dynamics for isolated molecules. However, TRPES for molecules with a time resolution even better than 100 fs has not been reported so far. The reason is that it is still difficult to generate pulses with a duration of less than 50 fs in deep-ultraviolet (DUV) or vacuum UV (VUV) regions. DUV or VUV pulses are often necessary for the TRPES since ionization potentials of many simple molecules are higher than 8 eV.