Time resolved VUV spectroscopy using synchrotron radiation: fluorescent lifetimes of atomic Kr and Xe

Synchrotron radiation from the Stanford positron electron accelerator ring (SPEAR) was used to excite the np⁵ (n + 1)s states in Kr (n = 4) and Xe (n = 5). Utilization of the excellent time structure of this facility made possible the first direct measurements of the lifetimes of these states. The results for Kr are (in jl coupling notation); τ(5s[ 3 2]1) = 3.18 ± 0.12 ns; τ(5s[ 1 2]1) = 3.11 ± 0.12 ns; for Xe, τ(6s[ 3 2]1) = 3.46 ± 0.09 ns; τ(6s[ 1 2]1) = 3.44 ± 0.07 ns. In addition the lifetime of the Xe 5p⁵[ 3 2]5d[ 3 2] J = 1 state was found to be 1.40 ± 0.07 ns. Effects due to radiation trapping are discussed.