Femtosecond photoelectron spectroscopy of trans-stilbene above the reaction barrier

Femtosecond photoelectron spectroscopy was employed to study the excitation of trans-stilbene above the isomerization reaction barrier. Apart from the S1 contribution, evidence of a second electronic state is found based on two different transients measured across the photoelectron spectrum. Time Dependent Density Functional Theory calculations on S0, S1, S2 and D0, together with simulations of the electron energy distribution support the experimental findings for selective photoelectron energies of the S0, S1,… electronic states.