Absolute differential cross sections for the electron impact excitation of the 12S→22S+22P levels of atomic hydrogen at 50 and 100 eV

Absolute experimental differential cross sections for the electron impact excitation of the 1(2)S --> 2(2)S + 2(2)P levels of H at 50 and 100 eV incident energy are obtained using an application of the method of mixtures and available accurate He (n = 2) experimental electron impact excitation differential cross sections. The determination of the number density composition of the mixed beam is made from energy loss measurements of the mixed beam at 200 eV and 25 degrees scattering angle using accurate H and He theoretical differential cross sections obtained from the distorted-wave Born approximation [D.H. Madison (private communication)] and convergent close coupling [I. Bray and A. Stelbovics, Phys. Rev. A 46, 6995 (1992); D. V. Fursa and I. Bray, Phys. Rev. A 52, 1279 (1995)].