B Energy Transfer In Electron and Photon Experiments

For a molecule AB, we may compare the processes of photoabsorption and electron-impact excitation as follows  

Since ionization is only a special case of excitation it is also possible to simulate the photoionization process using fast electrons. We may compare the processes 

It is apparent that in both cases energy E is deposited in [AB+ +eej] and that, as in the case of excitation, the photon energy is analogous to the electron energy loss. However, since there are now two electrons sharing the excess energy in electron-impact ionization, it is necessary to use time correlation (coincidence techniques) for the simulation of photoionization 

PHOTON EXPERIMENT ELECTRON-IMPACT EQUIVALENT TYPICAL REFERENCES 

Photoelectron spec- ejected electron, coincidence (e, 2e) Electron energy loss—selected 23,194 

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