Unlocking the performance of the BlueGene/L supercomputer
George Almasi, Siddhartha Chatterjee, et al.
ACM/IEEE SC 2004
This paper proposes methods for calculating the derivative couplings between adiabatic states in density-functional theory (DFT) and compares them with each other and with multiconfigurational self-consistent field calculations. They are shown to be accurate and, as expected, the costs of their calculation scale more favorably with system size than post-Hartree-Fock calculations. The proposed methods are based on single-particle excitations and the associated Slater transition-state densities to overcome the problem of the unavailability of multielectron states in DFT which precludes a straightforward calculation of the matrix elements of the nuclear gradient operator. An iterative scheme employing linear-response theory was found to offer the best trade-off between accuracy and efficiency. The algorithms presented here have been implemented for doublet-doublet excitations within a plane-wave-basis and pseudopotential framework but are easily generalizable to other excitations and basis sets. Owing to their fundamental importance in cases where the Born-Oppenheimer separation of motions is not valid, these derivative couplings can facilitate, for example, the treatment of nonadiabatic charge transfers, of electron-phonon couplings, and of radiationless electronic transitions in DFT.© 2005 American Institute of Physics.
George Almasi, Siddhartha Chatterjee, et al.
ACM/IEEE SC 2004
Alessandro Curioni, Tiziana Mordasini, et al.
J. Comput. Aided Mol. Des.
Salomon R. Billeter, Alessandro Curioni, et al.
Physical Review Letters
Kenneth C. Hass, William F. Schneider, et al.
Science