Initial and final state correlation effects in (E,3E) processes

In this work we investigate the process of double ionization of He by electron impact. The four-body continuum is described by a product of three Coulomb functions and the electron-electron correlation is included through distortion factors and effective charges. The initial state of the system is described by a product of a plane wave for the projectile and Hylleraas-like functions for the bound electrons. The Hylleraas-like functions here used satisfy the Kato cusp conditions at all the two-body coalescence. The fivefold differential cross section for double ionization of He is evaluated with the functions introduced. The effect of the correlation both in the initial as well as in the final channel are studied.