Breakup of the S F 6 3 + photoion revealed by momentum correlation between fragments

Fragmentation of $\mathrm{S}\mathrm{F}_{6}{}^{3+}$, formed from $\mathrm{S}{\mathrm{F}}_{6}$ by absorption of soft x-ray photons, has been investigated using a momentum imaging time-of-flight spectrometer. We observe triple ion coincidences between two ${\mathrm{F}}^{+}$ ions and $\mathrm{S}\mathrm{F}_{m}{}^{+}$ where $m=0,\dots{},3$. Strong correlation between the momentum distributions of the two ${\mathrm{F}}^{+}$ ions is observed across all dissociation channels involving triple ion coincidences. We present a method of estimating the contribution of the neutral fragments to the kinematics of ion ejection based on the scalar triple product of the ion momentum vectors. The noncoplanarity of the three ion ejecta inferred in this manner allows us to discern the fragmentation sequence of $\mathrm{S}\mathrm{F}_{6}{}^{3+}$. The proposed sequence is loss of a neutral F followed by violent ejection of two ${\mathrm{F}}^{+}$ ions and gentle removal of remaining F atoms from $\mathrm{S}\mathrm{F}_{3}{}^{+}$.