Diatomic molecule of copper. An all-electron ab initio self-consistent- field-configuration-interaction study of Cu2

A theoretical study, at three levels of approximation [self-consistent field (SCF), multiconfiguration (MC)-SCF, and extensive configuration interaction CI of the valence electrons] is reported for the Cu2 system. In spite of the great improvement of the total energy for the system obtained with the MC-SCF and CI methods, the predicted bond length is too long. Some discussion on the possible causes of this disagreement with experimental equilibrium distance is given. © 1982 The American Physical Society.