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 N 2 + , CO + and CO 2 + ions, and the essential results are as follows: N 2 + B 2 Sigma u + , v=0, 60.6+or-0.6 ns; CO + B 2 Sigma + 54.3+or-1.8 ns; CO 2 + A 2 Pi u 108.3+or-1.4 ns; CO 2 + B 2 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 A 2 Pi u and B 2 Sigma u + states respectively of CO 2 + .