Determination of the Binding Energies in Aromatic Clusters: Resonance-Enhanced Multi-Photon Ionization and Mass Analyzed Threshold Ionization Investigation of the Dichlorobenzene–Argon Complexes

Abstract

Resonance-enhanced multi-photon ionization (REMPI) and mass-analyzed threshold ionization (MATI) spectroscopic investigations were applied to the van der Waals complexes of the three dichlorobenzene isomers with argon. From the REMPI spectra it is concluded that the argon atom is shifted towards the chlorine atoms during excitation for the ortho and the meta isomers while it stays in the middle of the ring for the para isomer. From the MATI spectra it was possible to determine the binding energies in the ion ground state to 617 cm−1 ± 15 cm−1, 529 cm−1 ± 125 cm−1 and 581 cm−1 ± 76 cm−1 for the para, the meta and the ortho isomer, respectively. Together with theoretical calculations binding energies in the neutral ground state were determined to be 426 cm−1 ± 16 cm−1 for all the three isomers.