Electron-Impact Double Ionization of He (1s2s 3S)

A time-dependent close-coupling method for three-electron atomic systems is used to calculate the electron-impact double ionization of the He ($1s2s$ $^3S$) excited state. Partial cross sections are calculated for total angular momenta from $\cal{L}$ = 0 -5. An exponential fitting expression is used to extend the calculated partial cross sections to $\cal{L}$ = 6-40. The total cross sections at three different incident energies are compared with recent crossed-beams measurements and are found to lie with the experimental error bars. The magnitude of the double ionization cross section is found to be similar to that of the double ionization cross section from the ground state of he.