Perspective on "Theory of self-consistent electron pairs. An iterative method for correlated many-electron wavefunctions" - Wilfried Meyer (1976) J Chem Phys 64 : 2901

The title paper of Wilfried Meyer is a landmark for modern electron correla tion theories and their efficient implementation. It described for the firs t time a matrix-formulated direct configuration interaction method. This ap proach eliminates all coupling coefficients involving external orbitals and the need for a "formula tape". Secondly, a full integral transformation is avoided, a prerequisite for integral-direct implementations. Third, the th eory is formulated in a basis of nonorthogonal virtual orbitals (or atomic orbitals), which forms the basis of current local electron correlation trea tments. Meyer's paper, which was written while I was a diploma student in h is group, has strongly influenced my own work on multireference configurati on interaction, coupled-cluster theory, and local electron correlation meth ods. The current paper reviews the history of the self-consistent electron pairs method and describes its relation to current electron correlation tec hniques.