New models for mixing wavefunctions with density functional theory

The recent realization that the ground-state correlation energy of the random phase approximation (RPA) is intimately connected to an approximate coupled cluster doubles (CCD) model [1], opens interesting avenues for mixing RPA with DFT [2]. I will also present a new constrained-pairing mean-field theory (CPMFT) that describes strong correlations quite accurately [3,4]. Dynamical correlation functionals for this model are feasible but they require the use of ``alternative'' densities. \\[4pt] [1] G. E. Scuseria, T. M. Henderson, and D. C. Sorensen, J. Chem. Phys. \textbf{129}, 231101 (2008). \\[0pt] [2] B. G. Janesko, T. M. Henderson, and G. E. Scuseria, J. Chem. Phys. \textbf{130}, 081105 (2009). \\[0pt] [3] T. Tsuchimochi and G. E. Scuseria, J. Chem. Phys. \textbf{131}, 121102 (2009). \\[0pt] [4] G. E. Scuseria and T. Tsuchimochi, J. Chem. Phys. \textbf{131}, 164119 (2009).