Section Calculations at Low Energy

Having outlined the types of electron-molecule cross sections that are relevant in low-temperature plasmas, we turn to the calculation of such cross sections. Before examining particular computational techniques, it is instructive to consider the constraints that physical conditions and accuracy requirements place on the choice of calculational method. In this way, we shall better imderstand both the motivation behind the design of the methods in use today and the strengths and weaknesses of those methods. 

As we have just implied, solutions to the many-electron scattering problem, like solutions to the many-electron bound-state problems of quantum chemistry, are obtained in terms of products of one-electron functions, subject to constraints of spin, exchange antisymmetry (the Pauli principle), and possibly spatial (point 

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