Precision energy-level measurements and QED of highly charged ions

Abstract

A review is given of measurements involving the K-shell (np → 1s) transitions of hydrogenlike ions. In many experiments carried out, for example, on electron-beam ion traps and tokamaks, the calculated energies of the Lyman-series lines are utilized as calibration standards for measuring the energies of lines from more complex ions. Examples given include measurements of the transition energies of L-shell lines in neonlike ions. The Lyman lines of low-Z ions are also used as a bootstrap for measuring the contributions of quantum electrodynamics (QED) in very high-Z ions, such as U81+ and U89+. The lowest energy member of the Lyman series, Lyman-α, is commonly the target of absolute-energy measurements so as to test the reliability of the calculations of atomic structure in general and of the 1s QED terms in particular. A review of 42 measurements of 1s QED measurements indicates an apparent bias toward wanting to agree with calculations.PACS Nos.: 32.30.Rj, 31.30.Jv, 12.20.–m