Approximate density functional theory remains the method of choice in materials modeling for its balance of accuracy and efficiency. Nevertheless, challenges remain in the accurate treatment of correlated systems, e.g. transition metals with d or f electrons, which are disproportionately sensitive to well-known self-interaction error. We recently investigated the extent to which approximate methods for alleviating self-interaction error (i.e., DFT+U) recover desirable properties in DFT for transition metal chemistry, namely the derivative discontinuity and piecewise linearity. �I will review our observations on the relationship between linear response calculated U and the U at which E vs N curvature is eliminated. I will also discuss our recent observations to identify how density properties change as piecewise linearity is recovered from a more diverse set of methods (i.e., global and range separated hybrids as well as DFT+U) in comparison to accurate correlated wavefunction theory references. Finally, I will present some extended model Hamiltonians that provide a path forward to simultaneously improve densities and energetic delocalization error while minimizing static correlation error, as a path forward to improved transition metal chemistry materials modeling.

Understanding and eliminating delocalization error in transition metal chemistry

253rd National Meeting (2017)

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