Ultrafast dynamics of ethylbenzene cations probed by photofragmentation and photoelectron spectrometry

Ultrafast dynamics of ethylbenzene (EB) cation has been studied by time-resolved photofragmentation mass-spectrometry (PFMS) in combination with photoelectron spectrometry. EB cations were prepared by multiphoton ionization. The photoelectron spectrum was registered by photoelectron velocity map imaging (PEVMI) and the observed bands were assigned to different cation states. The ultrafast dynamics of these cation states are measured by monitoring the time dependent parent-ion depletion and the fragment-ion appearance, simultaneously. An ultrafast relaxation time of the parent ion of 2.50 (±0.13) ps has been inferred, which is attributed to a dissipative intramolecular vibrational redistribution (IVR) process within the D0 cation state. The results were compared with o-xylene cations, an isomer of EB.