Direct observation of correlation between electron emission and fragmentation into ions following B 1sexcitation of theBF3molecule

An alternative technique of coincidence between energy-selected electrons and mass- and energy-selected photoions, combined with angle-resolved photoion spectroscopy, has been applied to investigate the state-selected dissociation dynamics of the B 1s core-excited ${\mathrm{BF}}_3$ molecule. Dissociation from the spectator Auger final states both above and below the double-ionization threshold produces energetic ${\mathrm{B}}^{+}$ in the secondary processes of stepwise dissociation after the molecular deformation (${\mathit{D}}_{3\mathit{h}}$→${\mathit{C}}_{3\mathit{v}}$), in marked contrast to dissociation following B 1s ionization in which energetic ${\mathrm{F}}^{+}$ is ejected within the ${\mathit{D}}_{3\mathit{h}}$ plane of the parent ${\mathrm{BF}}_3$ molecule.