Asymmetric nuclear motion of theF1s–ionized state inBF3probed by quadruple-ion-coincidence momentum imaging

Abstract

Using the quadruple-ion-coincidence momentum imaging technique, we find that the momentum correlation of the four atomic ions departed from one ${\mathrm{BF}}_{3}^{4+}$ parent molecular ion produced via multiple Auger decay after $\mathrm{F}1s$ ionization exhibits asymmetric fragmentation in which the ${\mathrm{B}}^{+}$ ion is ejected in the direction opposite to one of the ${\mathrm{F}}^{+}$ ions. This observation provides evidence of symmetry lowering, from ${D}_{3h}$ to ${C}_{3v}$ in the $\mathrm{F}1s$--ionized state.