LMAXMIX: Difference between revisions
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Description: {{TAG|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 {{FILE|CHGCAR}} file. | Description: {{TAG|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 {{FILE|CHGCAR}} file. | ||
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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 | Higher ''l''-quantum numbers (''l''>{{TAG|LMAXMIX}}) are not handled by the [[:Category:Density mixing|density mixer]] (these components of the one-center charge density are set to the value corresponding to the present orbitals). Usually, it is not necessary to increase {{TAG|LMAXMIX}}, but the following 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) | *[[:Category:DFT+U|DFT+U calculations]] require, in many cases, an increase of {{TAG|LMAXMIX}} to 4 for ''d''-electrons (or 6 for ''f''-elements) to obtain fast convergence to the ground state. | ||
*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 | *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 not necessarily be identical to a self-consistent run. The deviations will be large for DFT+U calculations. For the calculation of band structures within the DFT+U approach, it is strictly required to increase {{TAG|LMAXMIX}} to 4 for ''d''-elements and to 6 for ''f''-elements. | ||
*[[:Category:Magnetism|SDFT calculations]] that consider noncollinear magnetism often require slow mixing of the spin density up to 4 for ''d''-elements and up to 6 for ''f''-elements to obtain fast convergence to the ground state. | |||
{{sc|LMAXMIX|Examples|Examples that use this tag}} | {{sc|LMAXMIX|Examples|Examples that use this tag}} | ||
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[[Category:INCAR tag]][[Category:Electronic minimization]][[Category: | [[Category:INCAR tag]][[Category:Electronic minimization]][[Category:Density mixing]] | ||
Revision as of 07:18, 13 July 2023
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 density mixer (these components of the one-center charge density are set to the value corresponding to the present orbitals). Usually, it is not necessary to increase LMAXMIX, but the following cases are exceptions:
- DFT+U calculations require, in many cases, an increase of LMAXMIX to 4 for d-electrons (or 6 for f-elements) to obtain fast convergence to the ground state.
- 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 not necessarily be identical to a self-consistent run. The deviations will be large for DFT+U calculations. For the calculation of band structures within the DFT+U approach, it is strictly required to increase LMAXMIX to 4 for d-elements and to 6 for f-elements.
- SDFT calculations that consider noncollinear magnetism often require slow mixing of the spin density up to 4 for d-elements and up to 6 for f-elements to obtain fast convergence to the ground state.