Configuration Interactions of Class 11: An Error in Cowan's Atomic Structure Theory
For about 35 years since its creation, the suite of atomic structure codes created by R. D. Cowan remains the working horse of atomic spectroscopists and is cited in more than 4000 publications. This note concerns one aspect of those codes: calculation of configuration interaction (CI) parameters. It was found that the last of the eleven classes of CI described in Cowan's book and implemented in his codes erroneously sets some of the CI parameters in Rydberg series of interacting configurations to zero. This leads to inaccurate description of eigenstates and sizeable errors in calculated transition probabilities.
Configuration Interactions of Class 11: An Error in Cowan's Atomic Structure Theory, Computer Physics Communications, [online], https://doi.org/10.1016/j.cpc.2017.02.003
(Accessed September 22, 2023)