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Resonant Formation of Ca+ From the Ca+ (4s25d1d2) level explained by autoionization through the 3d3/29f3/2Jπ=2 resonance

Published

Author(s)

Henrik Q. Lorensen, Harold V. Parks, E M. Spain, J E. Smedley, C H. Greene, S R. Leone

Abstract

The formation of Ca+ ions is measured in an effusive Ca beam by exciting through either the 4s4p1P1 state to highly excited Ca*(4snd1d2) Ryberg states. In agreement with previous work by McLaughlin and Duguette, when the Ryberg states are accessed through the 4s5p1P1 state, we detect a larfe increase in Ca+ ions for n=25, compared to other high n Ryberg states. It had been reprorted [Fabrikant; McLaughlin and Duguette] that ground stat-Ryberg state collisions cause this large increase in ion production and that the result provides a precise value of the electron affinity of Ca through the binding energy of the Ryberg electron. However, a variation of the origional experiment in which the same Ryberg states are accessed through the 4s4p1P1 level instead of the 4s4p1P1 level shows no enhancement of ions for any particular Ryberg level. With a three-laser experiment we show that the enhanced ionization effect for the 25d state is due to the 3d3/29f3/2Jπ=2 autoionizing resonance, which is coincidentally accessed from the Ca(4s25d1d2) state by the 808 nm photon involved in the original experiment by McLaughlin and Duquette. The existance of this resonance close to the experimentally observed energy is also established by R-Matrix calculations.
Citation
Physical Review A (Atomic, Molecular and Optical Physics)
Volume
54
Issue
No. 2

Keywords

autoionizing, calcium, electron affinity, Rydberg state

Citation

Lorensen, H. , Parks, H. , Spain, E. , Smedley, J. , Greene, C. and Leone, S. (1996), Resonant Formation of Ca+ From the Ca+ (4s25d<sup>1<sub></sub>d2</sup>) level explained by autoionization through the 3d<sub>3/2</sub>9f<sub>3/2</sub>J<sup>&#960;</sup>=2 resonance, Physical Review A (Atomic, Molecular and Optical Physics) (Accessed April 20, 2024)
Created July 31, 1996, Updated October 12, 2021