LINEAR SCALING COMPUTATION OF THE HARTREE-FOCK EXCHANGE MATRIX

Thresholding criteria are introduced that enforce locality of exchange interactions in Cartesian Gaussian-based Hartree-Fock calculations. T hese criteria are obtained from an asymptotic form of the density matr ix valid for insulating systems, and lead to a linear scaling algorith m for computation of the Hartree-Fock exchange matrix. Restricted Hart ree-Fock/3-21G calculations on a series of water clusters and polyglyc ine alpha-helices are used to demonstrate the O(N) complexity of the a lgorithm, its competitiveness with standard direct self-consistent fie ld methods, and a systematic control of error in converged total energ ies. (C) 1996 American Institute of Physics.