High-precision measurements of n = 2 → n = 1 transition energies and level widths in He- and Be- like Argon Ions
Jorge Machado, Csilla Szabo-Foster, Jose Paulo Santos, Pedro Amaro, Mauro Guerra, Guojie Bian, Jean-Michel Isac, Paul Indelicato
We have performed a reference-free measurement of the transition energies of the 1s2p1P1 → 1s2 1S0 line in He-like argon, and of the 1s2s22p 1P1 → 1s22s2 1S0 line in Be-like argon ions. The highly-charged ions were produced in the plasma of an Electron-Cyclotron Resonance Ion Source. Both energy measurements have been performed with an accuracy better than 2.0ppm, using a double flat-crystal spectrometer, without reference to any theoretical or experimental energy. The 1s2s22p 1P1 → 1s22s2 1S0 transition measurement is the first reference-free measurement for this core-excited transition. The 1s2p 1P1 → 1s2 1S0 transition measurement confirms recent measure- ment performed at the Heidelberg EBIT. The width measurement in He-like transition provide test of a radiative decay without Auger channels. In the case of the Be-like argon transition, the width results from the sum of a radiative channel and three main Auger channels. We have also performed ulticonfiguration Dirac-Fock (MCDF) calculations of transition energies and rates and done an extensive comparison with theory and other experimental data. Agreement with theory is excellent in both cases.
Physical Review A (Atomic, Molecular and Optical Physics)
, Szabo-Foster, C.
, Santos, J.
, Amaro, P.
, Guerra, M.
, Bian, G.
, Isac, J.
and Indelicato, P.
High-precision measurements of n = 2 → n = 1 transition energies and level widths in He- and Be- like Argon Ions, Physical Review A (Atomic, Molecular and Optical Physics), [online], https://doi.org/10.1103/PhysRevA.97.032517
(Accessed January 25, 2022)