Calculation of Rates of 4p–4d Transitions in Ar II

Alan Hibbert

doi:10.3390/atoms5010008

Abstract

Recent experimental work by Belmonte et al. (2014) has given rates for some 4p–4d transitions that are significantly at variance with the previous experimental work of Rudko and Tang (1967) recommended in the NIST tabulations. To date, there are no theoretical rates with which to compare. In this work, we provide such theoretical data. We have undertaken a substantial and systematic configuration interaction calculation, with an extrapolation process applied to ab initio mixing coefficients, which gives energy differences in agreement with experiment. The length and velocity forms give values that are within 10%–15% of each other. Our results are in sufficiently close agreement with those of Belmonte et al. that we can confidently recommend that their results are much more accurate than the early results of Rudko and Tang, and should be adopted in place of the latter.

Highlights

Some years ago, we [1,2,3] studied transitions among Ar II levels arising from configurations 3s2 3p5, 3s3p6, 3p4 3d, 3p4 4s, and 3p4 4p
We found that our calculations gave transition rates in close agreement with the experimental values recommended by Vujnović and Wiese [4], and gave much closer agreement between length and velocity forms of transition rates than were obtained by the only other major theoretical work, conducted by Luyken[5]
The values cited in the NIST tabulations [6] are taken from Bennett et al [7] where possible, in agreement with the recommended values given in [4], but for other 4p–4d transitions, it is the data of Rudko and Tang [8] which are quoted

Summary

Introduction

We [1,2,3] studied transitions among Ar II levels arising from configurations 3s2 3p5 , 3s3p6 , 3p4 3d, 3p4 4s, and 3p4 4p. Belmonte et al [9]—building on the work of Aparicio et al [10]—extended the experimental study to 4p–4d (and a few other) transitions They included results for some transitions between the lower-lying levels previously studied in [2,3,4], and found that they were in much closer agreement with the experimental values recommended by Vujnović and Wiese [4], and with our previous calculations, than with other experimental work. By contrast, they found that their results differed by up to a factor of five from the experimental values of Rudko and Tang [8]

Objectives

Methods

Results

Discussion

Conclusion