Electron Ionisation: Electric Field Interaction & Efficiency

[Orlando]

In electron ionisation, how does the electron beam transfer energy to the molecule being ionised? Is it via the interaction of the electric fields of the electrons in the molecule and the beam? If so, what type of interaction? And why is ionisation efficiency of the beam maximised when the wavelength of the beam is equal to that of the bond lengths in the molecule?

 

[chrisbaird]

This is not my are of expertise, but no ones seems to be answering, so I will give it a stab. I believe you have a resonance situation. When the wavelength of the beam matches up with the molecule bond lengths, they are in resonance, and the molecule is much more able to absorb the energy. (If you are not familiar with resonance, think of pushing a child on a swing. You get the highest swings if your rate of pushing matches the rate of swinging).