Theoretical computational methods relevant to low-energy electron scattering rely on variational principles. Variational theory appropriate to representation of the (N + 1)-electron scattering wave function in the form of Eq. (1.1) will be presented in this chapter. Direct computational application of this formalism is referred to here as the matrix variational method. Since it has been shown in Chapter 1 how the widely applied close-coupling method can be described by Eq. (1.1), the general variational argument to be given here also applies to that method, with some modifications of detail. In the algebraic close-coupling method this variational formalism, rather than numerical integration, is used to obtain solutions of the coupled equations as linear combinations of basis functions.
KeywordsVariational Principle Variational Theory Closed Channel Fixed Boundary Condition Channel Orbital
Unable to display preview. Download preview PDF.