The meaning of 'correlations' in the theory of multiphoton detachment; and reply

In view of recent developments in the theory of multiphoton detachment rates of real systems, we comment on the definition and computation of the effects of electron correlation in the discrete or the continuous spectrum. As an example, we present results on the four-photon ionization of H- from the application of our approach to the many-electron, many-photon problem, which includes the effects of electron correlation. When comparing them with the qualitative features of a recent experiment, good agreement is found. In theoretical investigations of multiphoton processes based on finite basis representations, correlations are handled via the structure of the basis. After a brief discussion of Fano correlations, we discuss the particular case of bases built with Slater-type functions. (author)