Measurement of absolute differential cross sections for the excitation of atomic hydrogen to its n=2 level by electron impact -: art. no. 052715

Using a crossed-beam method, we have measured absolute differential cross sections for the excitation of atomic hydrogen to its n = 2(2 S-2+2 P-2) level by electron impact. The angular range covered was from 12 degrees to 156 degrees in 12 degrees increments, while the impact energies treated were 15, 20, 30, and 40 eV. Absolute integrated excitation cross sections were calculated from the differential ones. Agreement of our data with other recent data and calculations is quite good, but there are still some discrepancies among our results and the older data.