Laserspectroscopic Investigation on heterosubstituted Halobenzenes by means of REMPI- and MATI-Spectroscopy

摘要

It is shown in this study that the correct reproduction of the experimental REMPI and MATI spectra by the FC-simulation is possible with the support through a (TD-)DFT approach. The used method (b3-lyp/aug-cc-pVTZ) provides reliable results for the geometrical and vibronic structures of 1,2,4- and 1,3,4-DCFB in their electronic ground, first excited and cationic ground states, within the given approximations. Moreover, we could show that the multidimensional Franck-Condon analysis is a powerful tool for the interpretation of REMPI and MATI spectra. The observation of an ever-recurring vibrational progression in the MATI spectra that emerges from one or more '△v=0 false origins' is new in this study and refines the understanding of vibrational modes active during the ionization process. Additionally we were able to apply MATI spectroscopy and FC-analysis to deduce some of the mechanisms that are active when an ion is formed in a two-photon process via resonance scrambled intermediate states (see ref. [4]).