Magnetic-sublevel differential cross sections for electron-impact excitation of He n1P levels: Theory and experiment in natural and atomic coordinate frames

Abstract

Abstract. Experimental data for the average transferred angular momentum, ( L ± ) , have been combined with experimental differential cross section [DCS] data for electron impact excitation of the 21p and 31p levels of helium to obtain the individual magnetic-sublevel differential cross-sections, [DCS~], in the natural (and atomic) coordinate system. First-order many-body theory (FOMBT) has been used to obtain corresponding theoretical predictions for DCS~ which are compared to these results. This comparison shows that F O M B T generally predicts M = +1 sublevel excitation DCS better than that for M = -I .