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arXiv · 1911.09170

Spontaneous electron emission from hot silver dimer anions: Breakdown of the Born-Oppenheimer approximation

E. K. Anderson·A. F. Schmidt-May·P. K. Najeeb·G. Eklund·K. C. Chartkunchand·S. Rosén·Å. Larson·K. Hansen·H. Cederquist·H. Zettergren·H. T. Schmidt
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Abstract

We report the first experimental evidence of spontaneous electron emission from a homonuclear dimer anion through direct measurements of $\rm{Ag}_2^- \rightarrow \rm{Ag}_2 + \rm{e}^-$ decays on milliseconds and seconds time scales. This observation is very surprising as there is no avoided crossing between adiabatic energy curves to mediate such a process. The process is weak but yet dominates the decay signal after 100 ms when ensembles of internally hot Ag$_2^-$ ions are stored in the cryogenic ion-beam storage ring, DESIREE, for 10 seconds. The electron emission process is associated with an instantaneous, very large, reduction of the vibrational energy of the dimer system. This represents a dramatic deviation from a Born-Oppenheimer description of dimer dynamics.

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E. K. Anderson, A. F. Schmidt-May, P. K. Najeeb, G. Eklund, K. C. Chartkunchand, S. Rosén, Å. Larson, K. Hansen, H. Cederquist, H. Zettergren, H. T. Schmidt. 2019-11-20. Spontaneous electron emission from hot silver dimer anions: Breakdown of the Born-Oppenheimer approximation. https://doi.org/10.1103/physrevlett.124.173001

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