Comparative characterization of two-electron wavefunctions using information-theory measures

Information-theory measures, in particular the Shannon entropy, Fisher information and statistical complexity, are used to discuss the variations among several commonly encountered model two-electron correlated wavefunctions. The Hookean, Moshinsky, and three-parameter Chandrasekhar wavefunctions are considered in real and momentum space, with further comparisons to the Hookean-Hartree-Fock (HF) wavefunction of Ragot, the numerical HF limit, and the hydrogenic (pure Coulomb) limit. The purpose of the study is to quantitatively analyze the effect of different models for inclusion of electron-electron correlation on information-theoretical measures, including statistical complexity, which characterize the electron distribution in position and momentum space.