Radiative decay probabilities of the (2s22p1/253s1/2)J=0 level in neonlike ions

The radiative decay rates of the (2s(2)2p(1/2)(5)3s(1/2))(J=0) level in neonlike ions have been calculated for nuclear charges ranging from Z = 10 to Z = 110. The calculations include the magnetic dipole decay to the (2s(2)2p(3/2)(5)3s(1/2))(J=1) level, which is shown to be the dominant decay branch in low-Z and very-high-Z ions, as well as the two-electron, one-photon decays to the (2s(2)2p(3/2)(5)3p(1/2))(J=1) and (2s(2)2p(3/2)(5)3p(3/2))(J=1) levels, which dominate near Z = 50. We also take into account a small magnetic quadrupole decay branch to the (2s(2)2p(3/2)(5)3s(1/2))(J=2) level and calculate the total radiative lifetime of the (2s(2)2p(1/2)(5)3s(1/2))(J=0) level. The resulting values span over 15 orders of magnitude, and much of this range is accessible with modern atomic lifetime measurement techniques. In particular, we calculate a value of 1.6 x 10(4) s(-1) for the radiative decay rate of the (2s(2)2p(1/2)(5)3s(1/2))(J=0) level in Fe XVII and show that the corresponding magnetic dipole transition has a measurable spectral intensity for electron densities below about 1 x 10(13) cm(-3).