Resonant two-photon ionization spectra of the van der Waals complexes: C6H5X⋅⋅⋅N2 (X=F, Cl, Br)

The one-color resonant two-photon ionization technique is employed to study jet-cooled van der Waals (vdW) clusters of halobenzene and nitrogen through the S0→S1 transition around the 0̄00 band. The spectra obtained exhibit rich information about the clusters’ intermolecular vdW vibrational modes and their solvent internal rotation. We have tentatively assigned all the observed spectral features to a single isomer of C6H5X⋅⋅⋅N2 (X=F, Cl, Br). The influence of X on the vdW vibrations and the internal rotation of N2 in the complex is investigated. The analysis of the influence of X on the 0̄00 spectral shift suggests that the change in vdW interaction energy upon electronic excitation is mainly due to the dispersion term.