Density Functional Theory

Development of exchange-correlation functionals

Development of exchange-correlation functionals

The XC energy contains all the quantum many-body effects beyond the simple Hartree approximation, and it is the subject of heavy investigations in different research groups worldwide. In particular, meta-generalized gradient approximation (meta-GGA) and, more in general, orbital-dependent functionals, are attracting strong interest due to their accuracy. Meta-GGA functionals depend not only on the gradient of the electronic density, but also on the Laplacian of the density and/or on the kinetic energy density, which allows to distinguish one-electron region. Orbital-dependent functionals depend on all orbitals and thus include exchange exactly.

In the Computation group at CBN, we develop meta-GGA and orbital-dependent XC functionals using model systems and exact conditions to fix the functional form and the numerical parameters within it. This allows to obtain accurate XC functionals without recurring to a heavy empirical parametrization.

Key References:
F. Della Sala, E. Fabiano, L. A. Constantin, Int. J. Quant. Chem. 116, 1641 (2016)
E. Fabiano, P Gori-Giorgi, M. Seidl, F. Della Sala, J. Chem. Theory. Comput. 12, 4885 (2016)