Precision spectroscopy of trapped highly charged heavy elements: pushing the limits of theory and experiment

Abstract

Atomic spectroscopy results from the electron beam ion trap at the National Institute of Standards and Technology have generally agreed with the predictions of theory extremely well. An interesting exception is our recent result on the helium isoelectronic sequence at Z = 22, which agrees instead with a meta-analysis of all prior measurements above Z = 15, but disagrees with both theory and a contemporaneous report of an independent measurement at Z = 18 which claims to validate theory to high accuracy. Here, a potential systematic shift involving high-n satellite lines induced by double charge exchange is quantitatively estimated and shown to be potentially significant in experiments involving gasses. Suggestions for further refinements in estimating the magnitude of this systematic shift are given.