MEASUREMENT OF THE LIFETIME OF THE 3P2 AND 4P5/2 STATES IN AR-16+ AND AR-15+

Promptly decaying levels in Li- and Be-like Ar could be identified in the delayed x-ray and electron spectrum in addition to the four known metastable (1 s2 s)1S0, (1 s2 s)3S1, (1 s2 p)3P2, and (1 s2 s2 p)4P5/2 states in He- and Li-like systems. The states having lifetimes of about 10-14s still contribute to the spectrum observed 10-9s after the ions have passed a foil. This observation is explained by cascading processes from states of high principal quantum number n≧14. The measured lifetime of the4P5/2 state subtracting the contribution of cascades is (0.594±0.016) ns and slightly larger than the theoretically predicted value of 0.563 ns. The3P2 state is depopulated at short distances behind the foil by cascading processes. Its measured lifetime of (1.44±0.08) ns compares to a theoretical value of 1.48 ns. © 1979 Springer-Verlag.