Asymmetric nuclear motion of the [Formula Presented]–ionized state in [Formula Presented] probed 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 [Formula Presented] parent molecular ion produced via multiple Auger decay after [Formula Presented] ionization exhibits asymmetric fragmentation in which the [Formula Presented] ion is ejected in the direction opposite to one of the [Formula Presented] ions. This observation provides evidence of symmetry lowering, from [Formula Presented] to [Formula Presented] in the [Formula Presented]–ionized state. © 2004 The American Physical Society.