Numerical calculations of the $2E1$ and $M1\mathrm{}$ decay rates of the $2s_{\frac{1}{2}}$ metastable states of the hydrogen isoelectronic sequence are presented. The $2E1$ rates are found to be in good agreement with recent calculations of Goldman and Drake, but substantially different from the earlier numerical values of Johnson. Effects of nuclear finite size on the $2E1$ rates are found to be insignificant, whereas finite-size effects reduce the $M1\mathrm{}$ rate by about 1.1% at $Z=92\mathrm{}$.

• Received 23 March 1982

DOI:https://doi.org/10.1103/PhysRevA.26.1142