The effect of wave function orthogonality on the simultaneous ionization and excitation of helium.

Within the framework of the first-order Born approximation, the triple differential cross sections (TDCSs) for simultaneous ionization and excitation of helium are calculated. The wave function of the ejected electron is chosen to be orthogonal or non-orthogonal to the wave function of the bound electron before ionization. It is found that the orthogonality has a strong effect on the TDCS, especially when plane waves and Coulomb waves are used to describe the projectile and the ejected electron. [ABSTRACT FROM AUTHOR]