Radiative lifetimes of the bound excited states of Pt^-

The intrinsic radiative lifetimes of the 5d^106s ^2S_1/2 and 5d^96s^2 ^2D_3/2 bound excited states in the platinum anion Pt^- 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 5d^106s ^2S_1/2 state was measurement to be 2.54±0.10 s, while only a lifetime in the range of 50 - 200 ms could be estimated for the 5d^96s^2 ^2D_3/2 fine-structure level. The storage lifetime of the Pt^- ion beam was measured to be a little over 15 minutes at a ring temperature of 13 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.