Near-threshold photodetachment of theLi−ion

Abstract

The method of threshold-photodetachment spectroscopy has been used to measure the electron aSnity of Li. Changes in the partial cross sections for the resolved hv+Li (2'S)~Li(2 S)+e (ep) ( Sap) and h v+Li (2 'S)~Li(2 P)+e (es) ( Pcs) channels were separately investigated in the vicinity of the 2 P threshold. The near-threshold data in the Pcs channel were fitted to a Wigner law to determine a threshold photon energy of 19884.8+1.6 cm '. An electron affinity of 4980.9+1.6 cm (617.6+0.2 meV) is obtained upon subtraction of the well-known 2 P excitation energy. The position of the Wigner cusp in the Sap channel was measured to be 19882.4+4.0 cm ', in agreement with the more precise Pcs-channel threshold energy. PACS number(s): 32.80.Fb, 35.10.Hn 610 596248 608 615

Isotope shift in the electron affinity of lithium

“…The most accurate experimental 7 Li EA is likely the results of 4984.90͑17͒ cm −1 reported by Haeffler et al 8 However, the uncertainty of 0.17 cm −1 is still too high to allow distinction between the EAs of 6 Li and 7 Li. Thus, as the results of this work will show, the theoretical calculations are significantly more accurate in this case than the available experimental results.…”

“…Even though there have been experiments concerning the EA of 7 Li, [4][5][6][7][8] there have been no reports on the measurement of the 6 Li electron affinity. The most accurate experimental 7 Li EA is likely the results of 4984.90͑17͒ cm −1 reported by Haeffler et al 8 However, the uncertainty of 0.17 cm −1 is still too high to allow distinction between the EAs of 6 Li and 7 Li.…”

“…Thus, as the results of this work will show, the theoretical calculations are significantly more accurate in this case than the available experimental results. These calculations will hopefully challenge the experiment to remeasure the 7 Li EA more accurately and to find a way for performing a similar measurement for 6 Li. The lithium EA has been a subject of numerous theoretical calculations.…”

“…9 More recently two high accuracy calculations on the 7 Li EA were reported. 10,11 In the work by Pachucki and Komasa, 10 the INM variational calculations on 7 Li and 7 Li − employing explicitly correlated Gaussians were performed first and the INM wave functions for these systems were subsequently used to calculate the finite-mass corrections, as well as the relativistic and QED corrections. In Ref.…”

Two Electron Dynamics in Photodetachment

“…The cross section for photodetachment of an electron from the Li − ion has previously been investigated, both experimentally [14] and theoretically [15]. Earlier laser studies have focused on the region around the first and second detachment thresholds.…”