Modelling the Dissociation Dynamics and Threshold Photoelectron Spectra of Small Halogenated Molecules
The two experimental aspects of the imagining photoelectron photoion coincidence (iPEPICO) apparatus which is stationed at the VUV Beamline at the Swiss Light Source, a synchrotron source, have been used to investigate the fundamental properties of small molecules in the gas phase. The fast and slow dissociation dynamics of halogenated methanes and fluorinated ethenes have been investigated using threshold photoelectron photoion coincidence (TPEPICO) techniques. Rate constants and accurate 0 K appearance energies for the formation of subsequent daughter ions have been determined. The latter values have been used in conjunction with ab initio calculations to derive updated enthalpies of formation. The valence threshold photoelectron spectra of four fluorinated ethenes have been recorded. The spectra have been analysed using Franck Condon simulations to model the vibrational structure, and assign the spectra, sometimes revising previous assignments. The potential energy surfaces of the ground and excited electronic states have been explored to uncover their various intriguing dissociative photodissociation mechanisms.