Dissociative photoionization studies of ethyl iodide using synchrotron radiation photoionization mass spectrometry and photoelectron imaging

[Display omitted] •The photoionization of C2H5I under light field were studied by SR-PIMS and PEI.•The stepwise dissociation of C2H5I under synchrotron radiation was studied.•The dissociation pathway was determined according to experiments and calculation. The stepwise dissociative photoionization of ethyl iodide(C2H5I) has been investigated via synchrotron radiation photoionization mass spectrometry and photoelectron imaging spectroscopy. By using VUV synchrotron radiation as excitation source, the photoionization and stepwise dissociative photoionization of C2H5I were observed by tuning the photon energy from 8.5 to 14.0 eV. The ionization energy of C2H5I was measured to be 9.33 ± 0.05 eV, and the appearance energies of C2H5+, C2H4+, C2H3+ were also determined according to the photoionization efficiency spectra. The possible pathways of the stepwise dissociation of C2H5I were determined by combining the experiments with theoretical calculation based on DFT. Finally, the multi-photon ionization process of C2H5I molecule was further studied via intensity-dependent photoelectron imaging spectroscopy.