Bodi Andras, Hafliðason Arnar, Kvaran Ágúst
Laboratory for Synchrotron Radiation and Femtochemistry, Paul Scherrer Institute, 5232 Villigen, Switzerland.
Science Institute, University of Iceland, Dunhagi 3, 107 Reykjavík, Iceland.
Phys Chem Chem Phys. 2023 Mar 8;25(10):7383-7393. doi: 10.1039/d2cp03339a.
Iodomethane yields ten fragment ions after valence photoionization, in part by multiple dissociation pathways for each, thanks to a plethora of electronic states available in the parent ion as well as in the fragments. The comprehensive breakdown diagram from 11 eV to the double ionization onset, , 26.7 eV, is recorded at high resolution using double imaging photoelectron photoion coincidence spectroscopy with synchrotron vacuum ultraviolet radiation. Based on fragment ion groupings, the changing branching ratios between these groups and between fragment ions within each group, as well as ancillary thermochemistry, we provide an overview of the dissociation pathways at play. Statistical and impulsive dissociations are identified using kinetic energy release analysis. Finally, a newly observed regime change is discussed in double ionization, whereby coincident H + I formation dominates over a 4 eV photon energy range, outcompeting the normally prevailing CH + I channel.
