Radiative lifetimes of the bound excited states of Pt

The intrinsic radiative lifetimes of the $5{d}^{10}6{s}^{}^{2}S_{1/2}$ and $5{d}^{9}6{s}^{2} ^{2}D_{3/2}$ bound excited states in the platinum anion ${\text{Pt}}^{\ensuremath{-}}$ have been studied at cryogenic temperatures at the Double ElectroStatic Ion Ring Experiment (DESIREE) facility at Stockholm University. The intrinsic lifetime of the higher-lying $5{d}^{10}6{s}^{} ^{2}S_{1/2}$ state was measured to be $2.54\ifmmode\pm\else\textpm\fi{}0.10\phantom{\rule{0.16em}{0ex}}\mathrm{s}$, while only a lifetime in the range of 50\char21{}200 ms could be estimated for the $5{d}^{9}6{s}^{2} ^{2}D_{3/2}$ fine-structure level. The storage lifetime of the ${\text{Pt}}^{\ensuremath{-}}$ ion beam was measured to be a little over 15 min at a ring temperature of $13\phantom{\rule{0.16em}{0ex}}\mathrm{K}$. The present study reports the lifetime of an atomic negative ion in an excited bound state with an electron configuration different from that of the ground state.