DFT Code Research Articles

Parallelization of a relativistic DFT code

We describe the implementation of some parallelization schemes for a relativistic four-component Dirac–Kohn–Sham program (BERTHA). The coulomb matrix construction has been parallelized by block-distributing the two-electron integral calculation, while for the exchange-correlation the numerical integration grid was distributed. Both schemes yield excellent performance results in terms of speed-up and scalability. The results obtained widen considerably the range of applicability of the method.

Stable DFT codes and frames

Discrete Fourier transform codes (DFT codes) or real number codes have been studied and recognized as useful (as joint source-channel codes, for example) but are not stable under bursty losses. This paper introduces a two-channel DFT code with an interleaver and shows that its numerical stability far exceeds that of the corresponding single-channel DFT code (the ratio of the frame bounds for the two-channel system can be smaller by many orders of magnitude). This leads to a stable way of dealing with bursts of errors using DFT codes.

A density functional study of CO 2 adsorption on the (100) face of Cu(9,4,1) cluster model

The adsorption modes of inert CO 2 on the (100) face of Cu(9,4,1) cluster model have been studies by the Slater DFT code of the Amsterdam density functional (ADF) program. The side-on adsorption mode with near linear CO 2 lying at the short bridge site has the highest binding energy of 26.31 kJ mol −1. The binding energies of CO 2 in similar geometry on the cross bridge, hollow, and on-top sites vary from 19.66 to 21.8 kJ mol −1. The investigation also revealed that a number of CO 2 bent modes with O-C-O angles equal to ≈ 150° can coordinate with the surface with binding energies ranging from 9.66 to 23.56 kJ mol −1. Further calculations indicated that to cause the CO 2 molecule to bend to ≈ 150°, there is negative 9.66 to 23.56 kJ mol −1. Further calculations indicated that to cause the CO 2 molecule to bend to ≈ 150°, there is negative charge transferred from the copper cluster to the CO 2 molecule.