Classical cross sections for ionization of hydrogen atoms by electrons
R Abrines; I C Percival; N A Valentine
Журнал:
Proceedings of the Physical Society
Дата:
1966-11-01
Аннотация:
Classical Monte Carlo cross sections are obtained for the ionization from the ground level of the hydrogen atom by electrons with twelve energies E between threshold and 540 ev. Statistical errors are about 5% down to E = 43 5 ev, and become relatively larger as the cross section decreases towards the threshold, with the exception of E = 34 ev, where the calculations are more extensive. Cross sections are less than experiment at high energies, and greater at low energies, where there is a marked improvement on classical impulse approximations. Experiment and Monte Carlo cross sections agree at approximately 60 ev. The cross sections and energies are scaled so that they apply to atoms which are initially in excited levels, when the classical theory is better. The cross section is independent of the initial angular momentum l<sub>i</sub> of the bound electron, except for a slight bias towards high l<sub>i</sub>, especially at large modified impact parameter. The distribution of energy ΔE transferred to the bound electron is compared with Vriens' classical impulse approximation and the Born approximation. The classical impulse approximation is of little value for excitation.
455.5Кб