Tags / Variables

The function setdefaults will set all tags associated with the construction of POSCAR, KPOINTS, and INCAR files as well as all 23vaspAS function-specific tags to their default values. It will also set PRINTOUTPUT=true, UPDATEVARIABLES=true and RMFILES=false.

PRINTOUTPUT specifies wether the output of 23vaspAS functions shall be written to output.txt or not (true/false).
UPDATEVARIABLES specifies wether variables shall be updated automatically by 23vaspAS functions or not (true/false).
RMFILES specifies wether irrelevant files (i.e. everything except OUTCAR, OSZICAR, and other calculation specific output files - CONTCAR for relaxation, XDATCAR for moleculardynamics, etc.) shall be automatically deleted after running $VASP or not (true/false).

Similarly, the functions setstructuraldefaults, setkpointsdefaults, and setincardefaults will set all tags associated with the construction of POSCAR, KPOINTS, and INCAR files to their default values respectively.

Only three variables have no default and must allways be set explicitly:

VASP (string) sets the VASP command.
MAINDIR specifies the location of the directory in which the calculations shall be performed an where the output.txt file shall be written. (Usually MAINDIR=$(pwd)).
POTCAR (string) specifies the name of the POTCAR to be used. If multiple names are indicated (as in POTCAR="Na Cl") the POTCARs will be concatenated in that order to build a new POTCAR. Whenever you reset this tag, you should also run setdefaults.

GNUPLOT (sring) sets the gnuplot command. Unlike the previous three tags, this tag is only strictly necessary when the fitmurnaghan function is used - otherwise optional but very useful. If this tag is set, 23vaspAS automatically makes plots using gnuplot and stores them in .png format. Otherwise, only a gnuplot input file will be constructed for a later, manual excecution of gnuplot.
PYTHON (sring) sets the python command. This tag only has to be set when the fitbirchmurnaghan function is used.

Only two variables are associated with the construction of KPOINTS files:

KPOINTS_$structure (integer) sets the number of kpoints for the structure by the name of $structure. Let the value stored in KPOINTS_$structure be equal to n. If $structure is a crystal, then an n x n x n kpoint mesh will be used. If $structure is a surface, then an n x n x 1 kpoint mesh will be used. If $sturucture is a molecule, then a 1 x 1 x 1 kpoint mesh will be used regardless of what is stored in KPOINTS_$structure.
Default = 6 if $structure is a supercell (prefix "sup_") but = 12 otherwise.

Note that for convenience an exception is made on surfaces if VACUUM_SIZE_$structure = 0 and NUMBER_OF_LAYERS_$structure = number of atoms per building cell. If these conditions are met, a n x n x n kpoint mesh will be constructed just like in a bulk crystal structure. This is intended to simplify reference bulk energy calculations for surface energies (see surfaceenergy).

KGAMMA on the other hand is used to specify whether a Gamma centered mesh (KGAMMA=.TRUE.) or a Monkhorst pack mesh (KGAMMA=.FALSE.) shall be used.
Default = .TRUE.

Instead of constructing KPOINTS files, kpoint densities can also be specified in INCAR files - to do so you must set the following (INCAR) tag:

KSPACING - Default = [empty] (*)

23vaspAS will only add this tag to INCAR files if it is set to a numerical value - and if thats the case, KPOINTS files will not be constructed.

The defaults for structural variables are as follows (see crystals, surfaces, and molecules for their descriptions):

VOLUME_$structure - Default = 15
C_A_RATIO_$structure - Default = depends on the sutructure
B_A_RATIO_$structure - Default = depends on the sutructure
SHIFT_$n_$structure - Default = depends on the sutructure

NUMBER_OF_LAYERS_$structure - Default = 6
VACUUM_SIZE_$structure - Default = 10
LAYER_HIGHTS_$structure - Default = "defaulthights"
SELECTIVE_DYNAMICS_DEPTH_$structure - Default = 2

ADSORPTION_DISTANCE_$structure - Default = 2

MOLECULE_CELL_SIZE_$structure - Default = 10
MOLECULE_ASYMETRY_$structure - Default = 1
POSITION_ATOM_$n_$structure - Default = depends on the structure

SUPERCELL_FACTOR_$structure - Default = 2 (only for when $structure carries the prefix "sup_")

Every INCAR file constructed by 23vaspAS will include the following tags:

GGA - Default = "PE" (*)

ISTART - Default = 0 (*)
ICHARG - Default = 2 (*)

LWAVE - Default = ".FALSE." (*)
LCHARG - Default = ".FALSE." (*)
NWRITE - Default = 2

ALGO - Default = "Normal"
PREC - Default = "Normal"
NELM - Default = 100 (*)
EDIFF - Default = 1E-06 (*)

NOMEGA - Default = 12 (If ALGO=RPAR)

ENCUT - Default = 400 (*)
ISMEAR - Default = 1
SIGMA - Default = 0.2
ISYM - Default = 2

ISPIN - Default = 1
MAGMOM

KPAR - Default = 1
NCORE - Default = 1
LREAL - Default = ".FALSE."

OTHERINCARTAGS (string) can be used to add aditional INCAR tags besides the ones listed above to your INCAR files if needed. As in OTHERINCARTAGS="LMAXFOCKAE = 4 ; LFOCKAEDFT = T".

(*) Notice how these defaults do not allways reflect the defaults as they are found in the VASP wiki.

Other INCAR tags will be added when running certain functions. Check the descriptions of functions for more info.

One last input-related variable: If needed, it can be used to specify additional input files that should be considered in every calculation. Just specify the files location and the file in question will be coppied (can also be multiple files).

OTHERINPUTFILES - Default = ""

Besides the input-realted variables listed above, there are also output-related variables that are mainly used to store calculated results:

MAINENE (integer) specifies which energy is to be stored in the variable ENERGY_$structure. MAINENE=1 means "free energy" is used, MAINENE=2 means "energy without entropy" is used, and MAINENE=3 means "energy(sigma->0)" is used. - Default = 1

Function-specific tags:

RELREPETITIONS (integer) - Default = 1. See relaxation for more info.
RECALCBULK (true/false) - Default = true. See formation energies for more info.
RECALCSURFACE (true/false) - Default = true. See formation energies for more info.
ADDASYMMETRY

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