Lifetime of metastable Ne2+ ions measured at a heavy-ion storage ring

The radiative lifetime of the 2s2 2p4 1S0 level in Ne2+ ions has been measured by timeresolved observations of one of the electric-dipole forbidden decay branches, the magnetic dipole (M1) transition to the 2s2 2p4 3P1 level, on ions circulating in a heavyion storage ring. The result, a lifetime of 213 ± 4 ms, agrees within the mutual 2s errors with that of a recent measurement using a radiofrequency ion trap, but is expected to suffer less from possible systematic error. It also compares very well with two calculations that have been semiempirically corrected for experimental transition energies.