Abstract:
We use the concept of quantum entanglement to give a physical meaning
to the electron correlation energy in systems of interacting electrons.
The electron correlation is not directly observable, being defined as
the difference between the exact ground state energy of the many-electron
Schrödinger equation and the Hartree–Fock energy. Using the configuration
interaction method for the hydrogen molecule, we calculate the correlation
energy and compare it with the entanglement as a function of
the nucleus–nucleus separation. In the same spirit, we analyze a dimer of
ethylene, which represents the simplest organic conjugate system, changing
the relative orientation and distance of the molecules to obtain
the configuration corresponding to maximum entanglement.
Keywords:entanglement, electron correlation energy, interacting molecules.