howto:running_qe_computation
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howto:running_qe_computation [2019/09/02 08:02] – [Molecular dynamics] mtaillefumier | howto:running_qe_computation [2021/12/08 10:18] (current) – mtaillefumier | ||
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+ | ====== How to run calculations like Quantum ESPRESSO ====== | ||
+ | |||
+ | |||
===== Introduction ===== | ===== Introduction ===== | ||
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An other popular program for plane wave DFT is [[http:// | An other popular program for plane wave DFT is [[http:// | ||
SIRIUS. We will consider the simple case of silicium doped with germanium and | SIRIUS. We will consider the simple case of silicium doped with germanium and | ||
- | show how to convert a QE input file to cp2k input file. Files for this tutorial can be found [[https:// | + | show how to convert a QE input file to cp2k input file. Files for this tutorial can be found [[https:// |
=== Word of caution with the pseudo-potential files === | === Word of caution with the pseudo-potential files === | ||
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for cp2k input file. Note the presence of the keyword '' | for cp2k input file. Note the presence of the keyword '' | ||
which indicates that cp2k should treat the coordinates as given in the lattice | which indicates that cp2k should treat the coordinates as given in the lattice | ||
- | basis. Putting these two sections together, we have | + | basis. **The coordinates do not have to be given in the lattice basis, any format supported by cp2k will work**. Putting these two sections together, we have |
< | < | ||
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^ QE keyword ^ CP2K (SIRIUS) keyword | ^ QE keyword ^ CP2K (SIRIUS) keyword | ||
| nspins = 1, 2 | NUM_MAG_DIMS = 0, 1 | PW_DFT/ | | nspins = 1, 2 | NUM_MAG_DIMS = 0, 1 | PW_DFT/ | ||
- | | nocolin = true | NUM_MAG_DIMS = 2 | PW_DFT/ | + | | nocolin = true | NUM_MAG_DIMS = 3 | PW_DFT/ |
| electron_maxstep | NUM_DFT_ITER | PW_DFT/ | | electron_maxstep | NUM_DFT_ITER | PW_DFT/ | ||
| mixing_beta | beta| PW_DFT/ | | mixing_beta | beta| PW_DFT/ | ||
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Energy | Energy | ||
-------------------------------------------------------------------------------- | -------------------------------------------------------------------------------- | ||
- | valence_eval_sum | + | valence_eval_sum |
- | < | + | < |
- | < | + | < |
< | < | ||
- | < | + | < |
- | one-electron contribution : -81.39606791 | + | one-electron contribution : -81.17469111 |
- | hartree contribution | + | hartree contribution |
- | xc contribution | + | xc contribution |
- | ewald contribution | + | ewald contribution |
PAW contribution | PAW contribution | ||
- | Total energy | + | Total energy |
- | band gap (eV) : 0.36618436 | + | band gap (eV) : 0.34564591 |
- | Efermi | + | Efermi |
- | iteration : | + | iteration : |
- | converged after 11 SCF iterations! | + | converged after 12 SCF iterations! |
- | + | ||
- | | + | |
+ | | ||
</ | </ | ||
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you should obtain a file '' | you should obtain a file '' | ||
{{: | {{: | ||
+ | The total energy given by QE and CP2K/SIRIUS are shifted by a small offset. More generally, converting the input file from QE to CP2K is not a warranty to obtain the same results for the total energy. The reasons for this multiple : | ||
+ | * Indicating the same cutoff does not warranty the fft grid size. | ||
+ | * QE and SIRIUS treat the radial integrals interpolation differently | ||
+ | * The functional in QE do not use libxc by default, while CP2K/SIRIUS does. | ||
+ | * The minimization method is sensitive to the initial states. | ||
+ | For all these reasons, we should not try to compare results at the binary level. |
howto/running_qe_computation.1567411355.txt.gz · Last modified: 2020/08/21 10:15 (external edit)