TY - JOUR

T1 - Strong enhancement of Penning ionisation in cold Rydberg gases II: Tom and Jerry pairs for alkali-metal atoms

AU - Zalam, Alaa Abo

AU - Bruvelis, M.

AU - Miculis, Kaspars

AU - Beterov, Ilya

AU - Bezuglov, Nikolai N.

AU - Ekers, Aigars

AU - Fuso, Francesco

N1 - KAUST Repository Item: Exported on 2021-01-13

PY - 2021/1/8

Y1 - 2021/1/8

N2 - Penning 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 [1], 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 [1], 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.

AB - Penning 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 [1], 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 [1], 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.

UR - http://hdl.handle.net/10754/666873

UR - https://iopscience.iop.org/article/10.1088/1361-6455/abd9fe

U2 - 10.1088/1361-6455/abd9fe

DO - 10.1088/1361-6455/abd9fe

M3 - Article

SN - 0953-4075

JO - Journal of Physics B: Atomic, Molecular and Optical Physics

JF - Journal of Physics B: Atomic, Molecular and Optical Physics

ER -