Combining the advantages of semi-direct schemes and linear-scaling self-consistent field methods

Abstract

A new stored-integral self-consistent field (SCF) scheme is presented for both Hartree–Fock (HF) and density-functional theory (DFT), which combines the advantages originally attributed to the direct and also linear-scaling SCF methods with those of traditional indirect or semi-direct approaches. By storing the density-screened two-electron integrals in the first time-consuming SCF iteration, recalculation of integrals can be almost avoided in subsequent iterations as the one-particle density matrix is shown to be quite representative for the one in later iterations. For the dominant exchange-type contractions, speed-ups of typically 1.5–3.7 are observed.

Keywords:

• indirect
• semi-direct
• stored-integral
• SCF
• linear-scaling
• density-matrix based

Acknowledgement

C.O. acknowledges financial support by the Volkswagen Stiftung within the funding initiative ‘New Conceptual Approaches to Modeling and Simulation of Complex Systems.’.