Publications Details
Cubic-scaling algorithm and self-consistent field for the random-phase approximation with second-order screened exchange
The random-phase approximation with second-order screened exchange (RPA+SOSEX) is a model of electron correlation energy with two caveats: its accuracy depends on an arbitrary choice of mean field, and it scales as O(n 5) operations and O(n3) memory for n electrons. We derive a new algorithm that reduces its scaling to O(n3) operations and O(n2) memory using controlled approximations and a new self-consistent field that approximates Brueckner coupled-cluster doubles theory with RPA+SOSEX, referred to as Brueckner RPA theory. The algorithm comparably reduces the scaling of second-order Møller-Plesset perturbation theory with smaller cost prefactors than RPA+SOSEX. Within a semiempirical model, we study H2 dissociation to test accuracy and Hn rings to verify scaling. © 2014 AIP Publishing LLC.