Practical Aspects of Electron Ionization

Practical Aspects of Electron Ionization Fragmentation of Organic Ions and Interpretation of El Mass Spectra Electron ionization the classical key to organic MS and indispensable part of every introductory course... 

There is another aspect of electrochemistry which could be important, particularly in a practical sense, which is a consequence of the likely Injection of hot electrons of several eV energy at the cathode. Such electrons could cause molecular dissociation rather than ionization, as Kao (1984) has pointed out, since the energy for bond breaking is between 3.5 and 4.5 eV for hydrocarbons. The free-radicals produced would, by initiating polymerization, encourage the formation of insulating layers at the electrodes. This may be an important feature of the high-field conduction and breakdown processes to which insufficient attention has been paid. 

The kineties of eleetron-transfer reactions, which is also affected by the electrode potential and the metal-water interface, is more difficult and complex to treat than the thermodynamic aspects. While the theoretical development for electron transfer kinetics began decades ago, a practical implementation for surface reactions is still unavailable. Popular transition state-searching techniques such as the NEB method are not designed to search for minimum-energy reaction paths subject to a constant potential. Approximations that allow affordable quantum chemistry calculations to get around this limitation have been proposed, ranging from the electron affinity/ionization potential matching method to heuristic arguments based on interpolations. 

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