Entanglement in Quantum Chemistry: the role of the molecular orbitals

The use of the mutual information (MI) as a measure of the entanglement in molecular quantum systems has gained a consensus in recent years. A key aspect of this quantity is its dependence on the one-electron (orbital) basis set, even for wave functions that are invariant under unitary transformation of the orbitals, among which we focus on the Molecular Orbital (MO) to Orthogonal Atomic Orbital (OAO) transformation which allows what is known as the Orthogonal Valence Bond (OVB) reading of a MO wave function. In this seminar, after a presentation of the MO and OVB description of the hydrogen dimer, we investigate the role of the orbital basis set (delocalized or localized, following different strategies) for wave functions expressed as linear combinations of Slater determinants and we give the analytic expression for the MI for a few special cases.

References:
L. Tenti, S. Peeters, E. Giner, and C. Angeli,
Journal of Chemical Theory and Computation 20, 10861 (2024).