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arXiv · 1708.04938

Vibrational Feshbach Resonances Mediated by Nondipole Positron-Molecule Interactions

M. R. Natisin·J. R. Danielson·G. F. Gribakin·A. R. Swann·C. M. Surko
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Abstract

Measurements of energy-resolved positron-molecule annihilation show the existence of positron binding and vibrational Feshbach resonances. The existing theory describes this phenomenon successfully for the case of infrared-active vibrational modes which allow dipole coupling between the incident positron and the vibrational motion. Presented here are measurements of positron-molecule annihilation made using a recently developed cryogenic positron beam capable of significantly improved energy resolution. The results provide evidence of resonances associated with infrared-inactive vibrational modes, indicating that positron-molecule bound states may be populated by nondipole interactions. The anticipated ingredients for a theoretical description of such interactions are discussed.

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M. R. Natisin, J. R. Danielson, G. F. Gribakin, A. R. Swann, C. M. Surko. 2017-08-16. Vibrational Feshbach Resonances Mediated by Nondipole Positron-Molecule Interactions. https://doi.org/10.1103/physrevlett.119.113402

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