Excited state photoelectron spectroscopy of anisole

Abstract

Excited state photoelectron spectra of anisole have been measured using different excitation pathways. They have been chosen according to vibrational levels in the S₁ state as observed in the REMPI spectrum. The combination of extended ab initio calculations with the spectroscopic results leads to the frequencies and assignment of the 42 normal modes of the anisole cation and neutral anisole. A strong influence of the excitation pathway on the appearance of the photoelectron spectra has been observed. With increasing excitation energies the dominant signals in the spectrum are shifted to higher energy. The analysis of the spectra reveals that the major contribution to the intensity is caused by the population of vibrational combination states in the ion. Increasing the energy of the intermediate S₁ state changes the population of these final states selectively. In addition, the population of the ν_9b state is strongly supported by changes of the geometry in the S₁ intermediate state.