Quenching of magnetism in hexagonal graphene nanoflakes by non-local electron correlation

Non-local MP2-like electron correlation in DFT calculations employing the double hybrid dispersion corrected B2PLYD functional is found to systematically quench anti-ferromagnetism in a variety of hexagonal graphene nanoflakes. The scaling in size of the associated spin contamination demonstrates further the artefactual character of any spin-polarization of electron densities in singlet electronic states.