Excitation of an atom by electron-photon impact

V. M. Buǐmistrov, Л. И. Трахтенберг

Karl Blum, Hans Kleinpoppen

A density matrix formulation of atomic excitation by electron impact is given and applied to electron-photon coincidence experiments. Conditions are discussed under which coherent excitation can be expected.

Helmut Schwarz

Mevlüt Doğan, Hüseyin Ali Yalım

A brief review is given on development of electron-photon coincidence studies from electron impact of atoms. The theory of electron-photon correlations is outlined in detail in terms of cross sections of excited atoms and excited state charge clouds. The state of a target atom is determined by the various orientation and alignment parameters and the multipole moments of the excited atom. General considerations, such as coherence effects in impact excitation, the influence of fine and hyperfine structures in correlations are taken into account. The relationship between scattering amplitudes (including their phases) and target parameters is worked out for singlet and doublet transitions.

R. Dueren

M Piwi ski, D. Dziczek, Rajesh Srivastava +2 more

Experimental values of the electron impact coherence parameters for excitation of the 5 1 P 1 state of cadmium atoms are reported along with relativistic distorted-wave approximation calculations. The electron–photon coincidence technique has been used in measurements for incident electron energy 100 eV and at scattering angles 10°, 15°, 20°, 30° and 40°. Theoretical results are in good qualitative agreement with experimental data.