EGAS41 - Swansea University

41 st EGAS CP 14 Gdańsk 2009
A theoretical study of the isotope shift on electron affinity of
chlorine
T. Carette ∗ , M.R. Godefroid
SCQP, Université Libre de Bruxelles, 1050 Brussels, Belgium
∗ Corresponding author: tcarette@ulb.ac.be
If the electron affinity (EA) is well known for most of the elements, it remains a challenging
quantity to calculate. On the experimental side, the measurements of isotope shift (IS)
on electron affinity are limited by both resolution and sensitivity. In this case, theory can
eventually be of some help even though correlation plays a dominant role in negative ions
structure and, particularly, in the calculation of specific mass shift (SMS).
We report Multiconfiguration Hartree-Fock calculations on isotope shift in electron
affinity of chlorine. The present study solves the longstanding theory-observation sign
discrepancy between the calculated and measured specific mass shift contributions on
electron affinity of chlorine for the isotopes 37 and 35 [1].
Table 1: Electron affinities and isotope shifts calculated and measured using our calculated field
shift -0.003 (20) GHz.
Model EA (eV) SMS 37/35 (GHz) IS 37/35 (GHz)
Theory [1] +0.50 1.24
Theory (this work) 3.663 −0.495 0.253(20)
+ relativistic correction from [2] 3.611
Experiment [1] 3.613 0.22(14)
References
[1] U. Berzinsh, M. Gustafsson, D. Hanstorp, A. Klinkmüller, U. Ljungblad, A.M. Mårtensson
Pendrill, Phys. Rev. A 51, 231 (1995)
[2] G. de Oliveira, J.M.L. Martin, F. de Proft, P. Geerlings, Phys. Rev. A 60, 1034 (1999)
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