Two-color resonance enhanced multi-photon ionization and mass analyzed threshold ionization spectroscopy of 2-aminobenzonitrile and the CN substitution effect

Abstract Two-color resonance two-photon ionization and mass analyzed threshold ionization spectra of 2-aminobenzonitrile have been obtained. The band origin of the S 1  ←  S 0 transition and the precise ionization energy (IE) were determined to be 31,265 ± 2 cm −1 and 66,653 ± 5 cm −1 , respectively. The most active modes in the S 1 and D 0 states are related to the in-plane ring vibrations. The relative errors of IE estimated by CBS-QB3 and G4 are −0.18% and +1.47%, respectively. The theoretical calculations well support our experimental findings.