Accession Number:

ADA563880

Title:

Higher-Order Adaptive Finite-Element Methods for Kohn-Sham Density Functional Theory

Descriptive Note:

Electronic preprint

Corporate Author:

ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD

Report Date:

2012-07-03

Pagination or Media Count:

50.0

Abstract:

We present an efficient computational approach to perform real-space electronic structure calculations using an adaptive higher-order finite-element discretization of Kohn-Sham density-functional theory DFT. To this end, we develop an a priori mesh adaption technique to construct a close to optimal finite-element discretization of the problem. We further propose an efficient solution strategy for solving the discrete eigenvalue problem by using spectral finite-elements in conjunction with Gauss-Lobatto quadrature, and a Chebyshev acceleration technique for computing the occupied eigenspace. Using the proposed solution procedure, we investigate the computational efficiency afforded by higher-order finite-element discretizations of the Kohn-Sham DFT problem. Our studies suggest that staggering computational savings--of the order of 1000-fold--can be realized, for both all-electron and pseudopotential calculations, by using higher-order finite-element discretizations. On all the benchmark systems studied, we observe diminishing returns in computational savings beyond the sixth-order for accuracies commensurate with chemical accuracy, suggesting that the hexic spectral-element may be an optimal choice for the finite-element discretization of the Kohn-Sham DFT problem. A comparative study of the computational efficiency of the proposed higher-order finite-element discretizations suggests that the performance of finite-element basis is competing with the plane-wave discretization for non-periodic pseudopotential calculations, and is comparable to the Gaussian basis for all-electron calculations. Further, we demonstrate the capability of the proposed approach to compute the electronic structure of materials systems containing a few thousand atoms using modest computational resources, and good scalability of the present implementation up to a few hundred processors.

Subject Categories:

  • Quantum Theory and Relativity
  • Solid State Physics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE