IWAVPR: Difference between revisions
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*{{TAG|IWAVPR}}=1|11 Simple extrapolation of the charge density using atomic charge densities is done (eq. (9.8) in thesis G. Kresse). This switch is convenient for all kind of geometry optimizations (ionic relaxation | *{{TAG|IWAVPR}}=1|11 Simple extrapolation of the charge density using atomic charge densities is done (eq. (9.8) in thesis G. Kresse). This switch is convenient for all kind of geometry optimizations (ionic relaxation | ||
and volume/cell shape with conjugate gradient or Quasi-Newton methods, i.e. {{TAG|IBRION}}=1,2) | and volume/cell shape with conjugate gradient or Quasi-Newton methods, i.e. {{TAG|IBRION}}=1,2) | ||
*{{TAG|IWAVPR}}=2|12 A second order extrapolation for the orbitals and the charge density is done (eq. (9.9) in thesis G. Kresse).A must for ab-initio MD-runs. | *{{TAG|IWAVPR}}=2|12 A second order extrapolation for the orbitals and the charge density is done (eq. (9.9) in thesis G. Kresse). A must for ab-initio MD-runs. | ||
*{{TAG|IWAVPR}}=3|13 In this case a second order extrapolation for the orbitals, and a simple extrapolation of the charge density using atomic charge densities is done. | *{{TAG|IWAVPR}}=3|13 In this case a second order extrapolation for the orbitals, and a simple extrapolation of the charge density using atomic charge densities is done. | ||
This is obviously a mixture between {{TAG|IWAVPR}}=1 and 2, however, it is usually worse than {{TAG|IWAVPR}}=2. | This is obviously a mixture between {{TAG|IWAVPR}}=1 and 2, however, it is usually worse than {{TAG|IWAVPR}}=2. | ||
Revision as of 10:47, 16 January 2017
IWAVPR = 0 | 1 | 2 | 3 | 10 | 11 | 12 | 13
| Default: IWAVPR | = 2 | if IBRION=0 (MD) and 1,2 (relaxation) |
| = 0 | else (static calculation) |
Description: IWAVPR determines how orbitals and/or charge densities are extrapolated from one ionic configuration to the next configuration.
Usually the file TMPCAR is used to store old orbitals, which are required for the prediction.If IWAVPR is larger than 10, the prediction is done without an external file TMPCAR (i.e. all required arrays are stored in the main memory, this option works from version VASP.4.1). If IWAVPR is set to 10, the reader will set it to the following default values:
The following options are available for IWAVPR:
- IWAVPR=0 no extrapolation, usually less preferable if you want to do an ab initio MD or a relaxation of the ions into the instantaneous groundstate.
- IWAVPR=1|11 Simple extrapolation of the charge density using atomic charge densities is done (eq. (9.8) in thesis G. Kresse). This switch is convenient for all kind of geometry optimizations (ionic relaxation
and volume/cell shape with conjugate gradient or Quasi-Newton methods, i.e. IBRION=1,2)
- IWAVPR=2|12 A second order extrapolation for the orbitals and the charge density is done (eq. (9.9) in thesis G. Kresse). A must for ab-initio MD-runs.
- IWAVPR=3|13 In this case a second order extrapolation for the orbitals, and a simple extrapolation of the charge density using atomic charge densities is done.
This is obviously a mixture between IWAVPR=1 and 2, however, it is usually worse than IWAVPR=2.
Mind: We don't encourage this setting.