Measurement of the lifetimes of ionic excited states using the inelastic electron-photon delayed coincidence technique

Abstract

A modification of the inelastic electron-photon delayed coincidence technique is described which permits the measurement of the lifetimes of ionic excited states. The technique has been applied to measurements in the N₂ ⁺, CO⁺ and CO₂ ⁺ ions, and the essential results are as follows: N₂ ⁺ B² Sigma _u ⁺, v=0, 60.6+or-0.6 ns; CO⁺ B² Sigma ⁺ 54.3+or-1.8 ns; CO₂ ⁺ A² Pi _u 108.3+or-1.4 ns; CO₂ ⁺ B² Sigma _u ⁺ 117.4+or-2.1 ns. Also presented are two coincidence energy-loss spectra of the continua resulting from the excitation of the A² Pi _u and B² Sigma _u ⁺ states respectively of CO₂ ⁺.