Optimized Pseudostates, Intermediate-Energy Scattering, and Collective Modes in Atoms

Abstract

In many of the usual methods of calculating scattering amplitudes, a basis set is chosen in which to expand the wave function, and then the coefficients are optimized. We ask here, how does one, in addition, optimize the basis set. A natural outgrowth of the formalism is the concept of an "average inelastic channel" which could, under certain circumstances, be interpreted as a collective mode of excitation of the target.