Scattering Matrix Formulation of the Total Photoionization of Two-electron Atoms

Abstract

A rigorous derivation of an exact quantum-mechanical formula is presented for the total photoionization of two-electron atoms in terms of local scattering matrices that describe local dynamics separately in the inner anti the outer parts of a surface dividing the whole configuration space. The exact formula is a correct extension of a previously known formula that misses the contribution of the channels closed at the dividing surface. The validity of semiclassical treatments of the outer part can be examined by evaluating the contribution of channels closed at the dividing surface.