  We investigate a pair entanglement of electrons in diatomic molecule, modeled
as a correlated double quantum dot attached to the leads. The low-temperature
properties are derived from the ground state obtained by utilizing the
Rejec-Ramsak variational technique within the framework of EDABI method, which
combines exact diagonalization with ab initio calculations. The results show,
that single-particle basis renormalization modifies the entanglement-switch
effectiveness significantly. We also found the entanglement signature of a
competition between an extended Kondo and singlet phases.
