Models for Atomic Secondary Ions

Although an extensive amount of research has been carried out on the fundamentals of atomic secondary ion emission, there is still not yet a complete accepted nnderstanding of the active processes. In addition, there still remains conjecture concerning the accnracy/validity of some of the published data. 

In an attempt to simplify the foregoing discussions, only a select few models are covered. This starts, for historical reasons, with a brief overview of the Local Thermal Equilibrium model. This is covered in Section 3.3.2.I. The Bond Breaking model is then discussed in Section 3.3.2.2, followed by the Electron Tunneling model in Section 3.3.2.3. For completeness sake, the Kinetic Emission model is presented in Section 3.3.2.4 as this appears to be responsible for the production of multiply charged atomic ions from the elements hghter than Phosphoras. Although many other models have also been put forward, only these are covered as the latter three, in particular, represent those currendy accepted for the respective systems described. 

Some of the models not covered include, as listed in chronological order  

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