We have measured the lifetime of the 3p${\mathrm{}}^2$${\mathrm{P}}_{3\mathrm{/}2}$ level in Na-like ${\mathrm{Kr}}^{25+}$, using beam-foil excitation and cascade-corrected analysis. Our result, τ=45.2±2 ps, has half the uncertainty of previous experimental data for highly ionized Na-like ions, and permits an important test of theoretical methods. Recently, Hutton et al. [Phys. Rev. A 51, 143 (1995)] pointed out a seemingly systematic one-standard-deviation difference between theoretical and experimental f values of 3s${\mathrm{}}^2$${\mathrm{S}}_{1\mathrm{/}2}$-3p${\mathrm{}}^2$${\mathrm{P}}_{3\mathrm{/}2}$ transitions for Na-like ions with Z>20. Our more precise result indicates that these small differences are coincidental and insignificant, confirming the reliability of theoretical calculations for this system.

• Received 17 September 1996

DOI:https://doi.org/10.1103/PhysRevA.55.3229