Emily A. Carter of Princeton University is supported by an award from the Theoretical and Computational Chemistry program within the Division of Chemistry for research to develop methods that scale linearly both for molecules and materials. For molecular systems the PI is using the local multi-reference single and double excitation configuration interaction (MRSDCI) method and its size-extensive analog, MR averaged coupled pair functional (ACPF) theory. Materials are being studied via orbital-free density functional theory (OF-DFT). The PI will enforce linear scaling by reformulating this method into an "integral direct" O(N) approach that exploits pre-screening of two-electron integrals and computes those integrals via an auxiliary basis of plane waves. She is continuing to develop local pseudopotentials (LPSs) and to combine the LPS and spin-dependent pseudopotential (SDP) methods so that it may be possible to treat transition metals in OF-DFT. This work is having a broader impact by enhancing the accuracy, efficiency, and generality of available methods, which will be useful for the broader science and engineering community.
