Heavy N+ ion transfer in doubly charged N2Ar van der Waals cluster
Xiaolong Zhu, Xiaoqing Hu, Shuncheng Yan, Yi-Geng Peng, Wentian Feng, Dalong Guo, Yong Gao, Shaofeng Zhang, A. Cassimi, Jiawei Xu, Dongmei Zhao, DaPu Dong, Bang Hai, Yong Wu, Jianguo Wang, X. Ma
Abstract
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 Ne 8+ ions: (N 2 Ar) 2+ →N + +NAr + . The neighboring Ar atom decreases the $${\mathrm{N}}_2^{2 + }$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msubsup> <mml:mrow> <mml:mi>N</mml:mi> </mml:mrow> <mml:mrow> <mml:mn>2</mml:mn> </mml:mrow> <mml:mrow> <mml:mn>2</mml:mn> <mml:mo>+</mml:mo> </mml:mrow> </mml:msubsup> </mml:math> barrier height and width, resulting in significant shorter lifetimes of the metastable molecular ion state $${\mathrm{N}}_2^{2 + }$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msubsup> <mml:mrow> <mml:mi>N</mml:mi> </mml:mrow> <mml:mrow> <mml:mn>2</mml:mn> </mml:mrow> <mml:mrow> <mml:mn>2</mml:mn> <mml:mo>+</mml:mo> </mml:mrow> </mml:msubsup> </mml:math> ( $${{\mathrm{X}}^{1}}{\Sigma _{{\mathrm{g}}}^{+}}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msubsup> <mml:mrow> <mml:msup> <mml:mrow> <mml:mi>X</mml:mi> </mml:mrow> <mml:mrow> <mml:mn>1</mml:mn> </mml:mrow> </mml:msup> <mml:mi>Σ</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>g</mml:mi> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> </mml:mrow> </mml:msubsup> </mml:math> ). Consequently, the breakup of the covalent N + −N + bond, the tunneling out of the N + ion from the $${\mathrm{N}}_2^{2 + }$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msubsup> <mml:mrow> <mml:mi>N</mml:mi> </mml:mrow> <mml:mrow> <mml:mn>2</mml:mn> </mml:mrow> <mml:mrow> <mml:mn>2</mml:mn> <mml:mo>+</mml:mo> </mml:mrow> </mml:msubsup> </mml:math> 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.