Asymmetric nuclear motion of the F 1s–ionized state in BF3 probed by quadruple-ion-coincidence momentum imaging

Using the quadruple-ion-coincidence momentum imaging technique, we find that the momentum correlation of the four atomic ions departed from one BF34+ parent molecular ion produced via multiple Auger decay after F 1s ionization exhibits asymmetric fragmentation in which the B+ ion is ejected in the direction opposite to one of the F+ ions. This observation provides evidence of symmetry lowering, from D3h to C3v in the F 1s–ionized state