The adiabatic connection (AC) that has as weak-interaction expansion the Møller-Plesset (MP) perturbation series has been recently shown to have a large coupling-strength expansion in terms of functionals of the Hartree-Fock density. Based on these findings, in this talk, I will introduce functionals that approximate directly the MP AC by interpolating between MP2 and the large-coupling strength limit. These functionals have the same cost as double hybrids and capture non-covalent interactions (NCI) very accurately, without using dispersion corrections. They also fix well-known deficiencies of MP2 for noncovalent interactions. This new class of methods is thus competitive with state-of-the-art dispersion enhanced functionals and can even significantly outperform them for a variety of test sets. I will also devote special attention to non-covalent systems where standard DFT enhanced by dispersion correction suffer from large density-driven errors, such as charge-transfer complexes, and discuss how MP AC methods fix this problem.
University of California, Irvine, USA