Abstract
Systematic calculations of two-photon decay rates of metastable and states are presented for heliumlike ions with nuclear charges in the range . These calculations include retardation and are carried out using relativistic configuration-interaction wave functions that account for the Breit interaction. Photon energy distributions and total rates are given. The relativistic decay rates agree, to within two standard deviations, with precise measurements for heliumlike Ar, Ni, Br, Kr, and Nb. The calculated rates are 30% smaller than the corresponding nonrelativistic rates at high . The two-photon decay rates remain a factor of about of the corresponding rates throughout the helium isoelectronic sequence.
- Received 18 February 1997
DOI:https://doi.org/10.1103/PhysRevA.56.1288
©1997 American Physical Society