Abstract
We have used fast-ion-beam laser spectroscopy to measure the 1s2s-1s2 intervals in Be iii to an absolute accuracy of 1 part in . Our results are (in ): σ(1s2-1s2=28 864.6120(4), σ(1s21s2=26 853.0534(3), σ(1s21s2) =26 867.9484(3). These results are an improvement over previous measurements by nearly 3 orders of magnitude and show evidence of uncalculated O() relativistic corrections. Once those terms are computed, our measurement will allow QED calculations in two-electron atoms to be tested at the 100 ppm level.
- Received 25 May 1993
DOI:https://doi.org/10.1103/PhysRevLett.71.2188
©1993 American Physical Society