TY - JOUR
T1 - Towards grid-based density-functional theory methods
T2 - Optimized nonorthogonal orbitals and multigrid acceleration
AU - Fattebert, J.
AU - Bernholc, J.
PY - 2000
Y1 - 2000
N2 - We have formulated and implemented a real-space ab initio method for electronic structure calculations in terms of nonorthogonal orbitals defined on a grid. A multigrid preconditioner is used to improve the steepest descent directions used in the iterative minimization of the energy functional. Unoccupied or partially occupied states are included using a density matrix formalism in the subspace spanned by the nonorthogonal orbitals. The freedom introduced by the nonorthogonal real-space description of the orbitals allows for localization constraints that linearize the cost of the most expensive parts of the calculations, while keeping a fast convergence rate for the iterative minimization with multigrid acceleration. Numerical tests for carbon nanotubes show that very accurate results can be obtained for localization regions with radii of 8 bohr. This approach, which substantially reduces the computational cost for very large systems, has been implemented on the massively parallel Cray T3E computer and tested on carbon nanotubes containing more than 1000 atoms.
AB - We have formulated and implemented a real-space ab initio method for electronic structure calculations in terms of nonorthogonal orbitals defined on a grid. A multigrid preconditioner is used to improve the steepest descent directions used in the iterative minimization of the energy functional. Unoccupied or partially occupied states are included using a density matrix formalism in the subspace spanned by the nonorthogonal orbitals. The freedom introduced by the nonorthogonal real-space description of the orbitals allows for localization constraints that linearize the cost of the most expensive parts of the calculations, while keeping a fast convergence rate for the iterative minimization with multigrid acceleration. Numerical tests for carbon nanotubes show that very accurate results can be obtained for localization regions with radii of 8 bohr. This approach, which substantially reduces the computational cost for very large systems, has been implemented on the massively parallel Cray T3E computer and tested on carbon nanotubes containing more than 1000 atoms.
UR - http://www.scopus.com/inward/record.url?scp=0001439552&partnerID=8YFLogxK
U2 - 10.1103/PhysRevB.62.1713
DO - 10.1103/PhysRevB.62.1713
M3 - Article
AN - SCOPUS:0001439552
SN - 1098-0121
VL - 62
SP - 1713
EP - 1722
JO - Physical Review B - Condensed Matter and Materials Physics
JF - Physical Review B - Condensed Matter and Materials Physics
IS - 3
ER -