Many body theory of photoemission in the quadratic response formalism

Abstract

Many body Green's function techniques are applied to show that the three current correlation function relating the one photon photoemission current to the applied external field may be expressed by one and two particle correlation properties only for arbitrary many body interactions. An analysis of the double time derivative of the three current correlation function leads to a generalization for arbitrary many body interaction of a formula frequently used for calculations of the photocurrent in the independent electron model. Implications are discussed for the case that only electrostatic electron-electron interactions are present.