LMAXMIX: Difference between revisions
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Higher ''l''-quantum numbers (''l''>{{TAG|LMAXMIX}}) are not handled by the mixer (these components of the one-center charge density are simply set to the value corresponding to the present orbitals). Usually, it is not required to increase {{TAG|LMAXMIX}}, but the following two cases are exceptions: | Higher ''l''-quantum numbers (''l''>{{TAG|LMAXMIX}}) are not handled by the mixer (these components of the one-center charge density are simply set to the value corresponding to the present orbitals). Usually, it is not required to increase {{TAG|LMAXMIX}}, but the following two cases are exceptions: | ||
* | *DFT+U calculations require in many cases an increase of {{TAG|LMAXMIX}} to 4 for ''d''-electrons (or 6 for ''f''-elements) in order to obtain fast convergence to the groundstate. | ||
*The {{FILE|CHGCAR}} file will contain the one-center PAW occupancy matrices up to {{TAG|LMAXMIX}}. When the {{FILE|CHGCAR}} file is read and kept fixed in the course of the calculations ({{TAG|ICHARG}}=11), the results will be not necessarily identical to a self-consistent run. The deviations will be large for (S)DFT+U calculations. For the calculation of band structures within the (S)DFT+U approach, it is strictly required to increase {{TAG|LMAXMIX}} to 4 for ''d''-elements and to 6 for ''f''-elements. | *The {{FILE|CHGCAR}} file will contain the one-center PAW occupancy matrices up to {{TAG|LMAXMIX}}. When the {{FILE|CHGCAR}} file is read and kept fixed in the course of the calculations ({{TAG|ICHARG}}=11), the results will be not necessarily identical to a self-consistent run. The deviations will be large for (S)DFT+U calculations. For the calculation of band structures within the (S)DFT+U approach, it is strictly required to increase {{TAG|LMAXMIX}} to 4 for ''d''-elements and to 6 for ''f''-elements. | ||
Revision as of 13:08, 11 April 2022
LMAXMIX = [integer]
Default: LMAXMIX = 2
Description: LMAXMIX controls up to which l-quantum number the one-center PAW charge densities are passed through the charge density mixer and written to the CHGCAR file.
Higher l-quantum numbers (l>LMAXMIX) are not handled by the mixer (these components of the one-center charge density are simply set to the value corresponding to the present orbitals). Usually, it is not required to increase LMAXMIX, but the following two cases are exceptions:
- DFT+U calculations require in many cases an increase of LMAXMIX to 4 for d-electrons (or 6 for f-elements) in order to obtain fast convergence to the groundstate.
- The CHGCAR file will contain the one-center PAW occupancy matrices up to LMAXMIX. When the CHGCAR file is read and kept fixed in the course of the calculations (ICHARG=11), the results will be not necessarily identical to a self-consistent run. The deviations will be large for (S)DFT+U calculations. For the calculation of band structures within the (S)DFT+U approach, it is strictly required to increase LMAXMIX to 4 for d-elements and to 6 for f-elements.