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System | Who | Action |
|---|---|---|
Graphene with vacancy | Felix Studt | Increase Fermi Temp from 0.1 to 0.2, use cg |
Graphene with vacancy | Chris O'Grady | change nbands from -10 to -20, MixerDif(beta=0.03, nmaxold=5, weight=50.0) |
Nitrogenase FeVCo for CO2 reduction | Lars Grabow | use Davidson solver (faster as well?), although later jvarley said MixerSum |
Several surfaces | Andy Peterson | Broyden mixer with Beta=0.5 |
TiO2 | Monica Garcia-Mota | MixerSum(0.05,6, 50.) |
MnxOy | Monica Garcia-Mota | Broyden MixerSum |
Co3O4 | Monica Garcia-Mota | Davidson eigensolver, MixerSum(beta=0.05, nmaxold=5, weight=50) or MixerSum(beta=0.05, nmaxold=6, weight=100) |
MnO2 with DFT+U U=+2eV | Monica Garcia-Mota | Marcin suggests we disable the DipoleCorrectionPoissonSolver (not yet tested) |
MnO2 with DFT+U U=+2eV | Monica Garcia-Mota | Henrik Kristofferson suggests: convergence is easier with high U (U=4eV) and then |
MnO2 with DFT+U U=+2eV | Monica Garcia-Mota | (from Heine) increase U in steps of say 0.1 (or smaller) and reuse the density and/or wave functions from the previous calculation? This tends to reduce the problem of being trapped in meta-stable electronic states, and it also makes convergence easier. Monica later reported that this helped. |
Cu | Ask Hjorth Larsen | first mixer parameter should probably be 0.1 for faster convergence, because it has a low DOS at the Fermi level. (Other transition metals may require lower values.) |
Other tricks:
- To speed up the poisson solver, use something like gpts=h2gpts(h=0.18, atoms.get_cell(), idiv=8) to get a nicely divisible-by-large-power-of-2 grid. This helps the "multi grid" poisson solver.
- experiment with Fermi smearing to help improve convergence
- experiment with number of empty bands to help improve convergence
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