Heavy N+ ion transfer in doubly charged N2Ar van der Waals cluster

Abstract

Van der Waals clusters are weakly bound atomic/molecular systems and are an important medium for understanding micro-environmental chemical phenomena in bio-systems. The presence of neighboring atoms may open channels otherwise forbidden in isolated atoms/molecules. In hydrogen-bond clusters, proton transfer plays a crucial role, which involves mass and charge migration over large distances within the cluster and results in its fragmentation. Here we report an exotic transfer channel involving a heavy N+ ion observed in a doubly charged cluster produced by 1 MeV Ne8+ ions: (N2Ar)2+→N++NAr+. The neighboring Ar atom decreases the {mathrm{N}}_2^{2 + } barrier height and width, resulting in significant shorter lifetimes of the metastable molecular ion state {mathrm{N}}_2^{2 + }({{mathrm{X}}^{1}}{Sigma _{{mathrm{g}}}^{+}}). Consequently, the breakup of the covalent N+−N+ bond, the tunneling out of the N+ ion from the {mathrm{N}}_2^{2 + } potential well, as well as the formation of an N−Ar+ bound system take place almost simultaneously, resulting in a Coulomb explosion of N+ and NAr+ ion pairs.