Electron-impact excitation ofSi3+(3s→3p) using a merged-beam electron-energy-loss technique

For the first time, absolute cross sections for electron-impact excitation of a multiply charged ion have been measured using an electron-energy-loss technique. Cross sections for e+${\mathrm{Si}}^{3+}$(3s ${}_{}{}^2{}_{}{}^{}$ ${\mathit{S}}_{1/2}$)→e+${\mathrm{Si}}^{3+}$(3p ${}_{}{}^2{}_{}{}^{}$ ${\mathit{P}}_{1/2,3/2}$)-8.88 eV have been measured with an accuracy of ±20% (at 90% confidence level) over a narrow energy range (±0.6 eV) about the threshold energy with an energy resolution of 0.2 eV. Results are in good agreement with close-coupling calculations.