Mass analyzed threshold ionization (MATI) spectroscopy of trichlorobenzenes via different intermediate vibrational states in the S1 state

Two color resonant mass analyzed threshold ionization (MATI) spectroscopy was applied in order to investigate the ionic properties of the structural isomers of trichlorobenzene (TCB) above the ionization threshold. For the first time, vibrational spectra of the 35Cl3 and 35Cl237Cl isotopomers of 1,2,3-, 1,2,4- and 1,3,5-trichlorobenzene cations in their electronic ground state have been measured via different S1 intermediate states by mass analyzed threshold ionization (MATI) spectroscopy. Additionally ab initio calculations at DFT (density functional theory) and TDDFT (time-dependent density functional theory) have been performed to compare experimental findings with theory. From the MATI spectra the adiabatic ionization energies of the three isomers 1,2,3-TCB, 1,2,4-TCB and 1,3,5-TCB could be determined to 74289 ± 6 cm−1, 72779 ± 6 cm−1 and 74900 ± 100 cm−1, respectively. Several vibrational modes of the isotopomers have been assigned by comparison of the experimental and theoretical results.

Graphical abstractFigure optionsDownload full-size imageDownload high-quality image (63 K)Download as PowerPoint slideResearch highlights▶ Trichlorobenzenes exhibit various vibrational structures in ionic ground state. ▶ Jahn–Teller effect of 1,3,5-trichlorobenzene investigated. ▶ Ionization energies of trichlorobenzenes measured.