Experimental and (firstorder manybody) theoretical differential and integral cross sections for excitation of the n=3 states of He by electron impact at 29.2 and 39.7 eV
Abstract
Differential and integral electron scattering cross sections have been measured and calculated for the transitions 1^{1}S>3^{1}S, 3^{3}S, 3^{3}P and for the experimentally unresolved transitions 1^{1}S>3^{1}P, 3^{1,3}D in helium. Measurements were made relative to both the 2^{3}P and 2^{1}P transitions at incident electron energies of 29.2 and 39.7 eV, and over the angular range 5136°. The n=3 relative differential cross sections (DCS) were normalized to the absolute scale by utilizing known normalized absolute DCS for the 2^{3}P and 2^{1}P transitions. The theoretical calculations were carried out in the firstorder manybody theory of Csanak, Taylor, and Yaris. Comparisons are also made of the present measurements and calculations with other calculations carried out for the 3^{1}S, 3^{1}D, and 3^{1}P states in the Born and several Ochkurlike approximations. The theoretical origins in several theories of the intriguing sharp minimum in the 1^{1}S>3^{1}S DCS are discussed.
 Publication:

Physical Review A
 Pub Date:
 May 1975
 DOI:
 10.1103/PhysRevA.11.1583
 Bibcode:
 1975PhRvA..11.1583C
 Keywords:

 Atomic Excitations;
 Electron Impact;
 Electron Scattering;
 Helium;
 Scattering Cross Sections;
 Born Approximation;
 Electron States;
 Electron Transitions;
 Energy Dissipation;
 Many Body Problem;
 Atomic and Molecular Physics