Electron correlation studies by means of local-scaling transformations and electron-pair density functions

Electron correlation is one long standing problem of computational electronic structure theory. Even more, with the advent of the density functional theory and, in particular, with its Kohn–Sham implementation, the separation of the non-dynamical and dynamical components of the electron correlation has became an unavoidable requirement towards construction of reliable exchange-correlation functionals. In this paper, we address the analysis of the separation of the non-dynamical and dynamical electron correlation effects from two complementary viewpoints, namely, analysis of the correlation energy components and the analysis of the electron-pair density. The former approach will make use of the local-scaling transformations and the latter will be based on the study of intracule and extracule densities.Work supported by grant 9/UPV-00203.215-13527/2001of the Office of Universities and Research of the The Goverment of the Basque Country and, by grant BQU2001-0208 of the Spanish Ministry of Education and Science.Partially supported by grant G-97000741 of CONICIT of Venezuela.