Abstract
Something interesting usually happens when you excite a collision process close to its threshold. The energy of the incident particle (in the present case, an electron or a photon) is relatively small, ie just greater than the threshold energy of the reaction. Further, one or more electrons of very small energy (≤.01eV) can be produced. These conditions can have a profound influence on the collision. For example electron exchange can take place and electron-electron correlation effects can play a dominant role. Threshold excitation often leads to new and unexpected results. The present review deals with some of the characteristics of threshold excitation by electrons and photons and some of the aspects of the experimental techniques involved. As will be seen there are similarities betwen excitation by electrons and photons. For example the resonances observed in electron atom scattering have some similarities to the doubly excited states induced by photon excitation since both atomic systems consist of two electrons clinging to a positively charged core.
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References
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© 1988 Plenum Press, New York
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King, G.C. (1988). Threshold Measurements of Electron and Photon Collisions with Atoms and Small Molecules. In: Burke, P.G., West, J.B. (eds) Electron-Molecule Scattering and Photoionization. Physics of Atoms and Molecules. Springer, Boston, MA. https://doi.org/10.1007/978-1-4613-1049-5_7
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DOI: https://doi.org/10.1007/978-1-4613-1049-5_7
Publisher Name: Springer, Boston, MA
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