A three-photon fluorescence excitation study of the S(A1g)→S1(B2u) transition in neat liquid benzene

Abstract

The three‐photon fluorescence excitation spectrum of the S₀(A_1g)→S₁(B_2u) transition in neat liquid benzene is reported. For both linear and circular incident polarization, the electronic origin and its associated ν₁ Franck–Condon progression are observed. The appearance of the electronic origin in the neat liquid is contrasted with the results of previous studies demonstrating the surprising absence of the group‐theoretically allowed origin in the three‐photon spectra of benzene vapor and dilute benzene solutions.