Emission of quasifree electrons

The emission of electrons from liquids with Vq 0 is due to thermal activation. The process can be treated as in the case of thermionic emission from metals (Pathria, 

The momentum of the electron has to meet the conditions outlined in Section 6.2.2. Otherwise, the electron is reflected back into the liquid where subsequent scattering events randomize the momentum. The electron then returns to the barrier without any significant energy loss. The escape rate of electrons is increased by the application of an electric field as. 

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