(PARSEC) PARSEC is a computer code that solves the Kohn-Sham equations by expressing electron wave-functions directly in real space, without the use of explicit basis sets. It uses norm-conserving pseudopotentials (Troullier-Martins and other varieties). It is designed for ab initio quantum-mechanical calculations of the electronic structure of matter, within density-functional theory.
PARSEC is optimized for massively parallel computing environment, but it is also compatible with serial machines. A finite-difference approach is used for the calculation of spatial derivatives. Owing to the sparsity of the Hamiltonian matrix, the Kohn-Sham equations are solved by direct diagonalization, with the use of extremely efficient sparse-matrix eigensolvers. Some of its features are:
- Choice of boundary conditions: periodic (on all three directions), or confined.
- Structural relaxation.
- Simulated annealing.
- Langevin molecular dynamics.
- Polarizability calculations (confined-system boundary conditions only).
- Spin-orbit coupling.
- Non-collinear magnetism.