A UNIFIED REVIEW OF BLOCH OPERATOR MODIFIED KOHN VARIATIONAL-METHODS

A unified review of various Kohn variational methods for scattering ca lculations is presented using appropriate Bloch operators. Previous ex pressions are generalized slightly to use either an infinite range or a finite range of the scattering coordinate, or to use a basis set wit h non-fixed log derivative boundary conditions. A non-variational meth od (method of moments) is used in the derivations; the results are con firmed by Kohn variational derivations. Speculative linear variation f unctionals are introduced to connect both derivations. A model calcula tion of K (reactance) matrix is presented using a finite range and rea l algebra which is free of the so called 'Kohn anomaly', unlike the co nventional Kohn method for the K matrix.