Strong enhancement of Penning ionisation in cold Rydberg gases II: Tom and Jerry pairs for alkali-metal atoms
AuthorsZalam, Alaa Abo
Bezuglov, Nikolai N.
Online Publication Date2021-04-02
Print Publication Date2021-03-24
Embargo End Date2022-01-08
Permanent link to this recordhttp://hdl.handle.net/10754/666873
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AbstractPenning ionisation (PI) processes involving pairs of Rydberg alkali-metal atoms, excited to different quantum states and experiencing dipole-dipole interactions, have a wide range of important properties in atomic physics. Within the framework of the semi-classical approximation, we have used both numerical and analytical approaches to examine the Penning autoionisation width dependence on the state quantum numbers in a quasi-molecule formed by the interacting partner atoms. We described the characteristics of optimal quantum numbers that lead to enhanced PI widths for the interacting Rydberg atom pairs of all alkali-metal atoms. The excited states of atoms in these pairs are asymmetric, resulting in a large atomic shell size difference: inspired by , we call such pair "Tom" and "Jerry" (for "big" and "small"). Compared to symmetric pairs, the optimal asymmetric pairs display a significant (by several orders of magnitude) increase in the PI rate. This property makes PI a relevant source for producing charged particles in cold Rydberg systems that spontaneously evolve into cold plasma. Contrary to hydrogen atoms examined in , the difference of quantum defects in alkali-metal atoms results in a strong Penning width dependence on the orbital quantum numbers l of the quasi-molecule. In particular, alkali-metal atoms exhibit two PI channels associated with bound-bound optical transitions showing ∆l = ±1 - individual and closely spaced (doublet-like) configurations of optimal pairs. Furthermore, we demonstrate that the presence of Förster resonances can lead to a notable (up to 5 times) increase of the PI efficiency.
CitationZalam, A. A., Bruvelis, M., Miculis, K., Beterov, I., Bezuglov, N., Ekers, A., & Fuso, F. (2021). Strong enhancement of Penning ionisation in cold Rydberg gases II: Tom and Jerry pairs for alkali-metal atoms. Journal of Physics B: Atomic, Molecular and Optical Physics. doi:10.1088/1361-6455/abd9fe
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