Novel Short-Pulse Photoionization Electron Source:Li(1s2s2p)P°4Deexcitation Measurements in a Plasma

As a result of photoionization of rare-gas atoms by x rays emitted from a laser-produced plasma, high densities (> ${10}^{16}$ ${\mathrm{cm}}^{-3\mathrm{}}$) of hot (∼ 45-eV) electrons are produced in a pulse of ∼600 ps duration. Following excitation by means of this electron source, the deexcitation rate constant from the $\mathrm{Li}\mathrm{}\left(1s2s2p\right)\mathrm{}{}_{}{}^4{}_{}{}^{}P°$ level is measured to be 3×${10}^{-7\mathrm{}}$ ${\mathrm{cm}}^3$ ${\mathrm{s}}^{-1\mathrm{}}$ at an electron density of ∼${10}^{15}$ ${\mathrm{cm}}^{-3\mathrm{}}$.