INCAR: Difference between revisions

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'''Be very careful about the {{TAG|INCAR}} file, it is the main source of errors and false results!'''
'''Be very careful about the {{TAG|INCAR}} file, it is the main source of errors and false results!'''


The {{TAG|INCAR}} file is a tagged format free-ASCII file: Each line consists of a tag (i.e. a string) the equation sign '=' and a number of values. It is possible to give several parameter-value pairs ( tag = values ) on a single line, if each of these pairs are separated by a semicolon ';'. If a line ends with a backslash the next line is a continuation line. Comments are normally preceded by the number sign '#', but in most cases comments can be append to a parameter-value pair without the '#'. In this case semicolons should be avoided within the comment.  
The {{TAG|INCAR}} file is a tagged format free-ASCII file: Each line consists of a tag (i.e. a string) the equation sign '=' and a number of values. It is possible to give several parameter-value pairs ( tag = values ) on a single line, if each of these pairs are separated by a semicolon ';'. If a line ends with a backslash the next line is a continuation line (beware of blanks after the backslash, some versions of VASP might not accept those). Comments are normally to be preceded by the number sign '#', but in most cases comments can be append to a parameter-value pair without the '#'. In this case semicolons should be avoided within the comment.  


Lines with tabs are not properly read by VASP, please avoid using them in the INCAR.
Lines with tabs are not properly read by VASP, please avoid using them in the INCAR.
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  Electronic Relaxation 1
  Electronic Relaxation 1
   {{TAGBL|ENCUT}}  = 200.00 eV  
   {{TAGBL|ENCUT}}  = 200.00 eV  
   {{TAGBL|IALGO}}  =    18   algorithm
   {{TAGBL|ALGO}}  =    Normal   algorithm
   {{TAGBL|NELM}}  =    60;  {{TAGBL|NELMIN}} = 0; {{TAGBL|NELMDL}} =  3    # of ELM steps  
   {{TAGBL|NELM}}  =    60;  {{TAGBL|NELMIN}} = 0; {{TAGBL|NELMDL}} =  3    # of ELM steps  
   {{TAGBL|EDIFF}}  =  1E-04   stopping-criterion for ELM    
   {{TAGBL|EDIFF}}  =  1E-06   stopping-criterion for ELM
  {{TAGBL|BMIX}} = 2.0
  {{TAGBL|TIME}} = 0.05
   
   
  Ionic Relaxation
  Ionic Relaxation
   {{TAGBL|EDIFFG}} =  .1E-02  stopping-criterion for IOM
   {{TAGBL|EDIFFG}} =  -1E-02  stopping-criterion for IOM (all forces smaller 1E-2)
   {{TAGBL|NSW}}    =      9   number of steps for IOM
   {{TAGBL|NSW}}    =      10   number of steps for IOM
   {{TAGBL|IBRION}} = 2         
   {{TAGBL|IBRION}} = 2         
   
   
   {{TAGBL|POTIM}}  =   10.0   time-step for ion-motion
   {{TAGBL|POTIM}}  =   .5   time-step for ion-motion
  {{TAGBL|POMASS}} = 102.91
  {{TAGBL|ZVAL}}  =  11.0
   
   
  DOS related values:
  DOS related values:
   {{TAGBL|SIGMA}}  =    0.4;  {{TAGBL|ISMEAR}} =  1 broad. in eV, -4-tet -1-fermi 0-gaus
   {{TAGBL|SIGMA}}  =    0.05;  {{TAGBL|ISMEAR}} =  0 broad. in eV, -4-tet -1-fermi 0-gaus





Revision as of 15:31, 17 December 2020

The INCAR file is the central input file of VASP. It determines "what to do and how to do it". There is a relatively large number of parameters that may be set by means of tags in the INCAR file. Most of these parameters have convenient defaults, and a user unaware of their meaning should not change any of the default values.

Be very careful about the INCAR file, it is the main source of errors and false results!

The INCAR file is a tagged format free-ASCII file: Each line consists of a tag (i.e. a string) the equation sign '=' and a number of values. It is possible to give several parameter-value pairs ( tag = values ) on a single line, if each of these pairs are separated by a semicolon ';'. If a line ends with a backslash the next line is a continuation line (beware of blanks after the backslash, some versions of VASP might not accept those). Comments are normally to be preceded by the number sign '#', but in most cases comments can be append to a parameter-value pair without the '#'. In this case semicolons should be avoided within the comment.

Lines with tabs are not properly read by VASP, please avoid using them in the INCAR.

A typical (relative complex) INCAR is given as:

SYSTEM = Rhodium surface calculation

Start parameter for this Run:
  START =      0    job   : 0-new  1-cont  2-samecut
  ICHARG =      2    charge: 1-file 2-atom 10-const
  INIWAV =      1    electr: 0-lowe 1-rand

Electronic Relaxation 1
  ENCUT  = 200.00 eV 
  ALGO  =     Normal    algorithm
  NELM   =     60;   NELMIN = 0; NELMDL =  3    # of ELM steps 
  EDIFF  =   1E-06   stopping-criterion for ELM

Ionic Relaxation
  EDIFFG =  -1E-02   stopping-criterion for IOM (all forces smaller 1E-2)
  NSW    =       10   number of steps for IOM
  IBRION = 2         

  POTIM  =    .5    time-step for ion-motion

DOS related values:
  SIGMA  =    0.05;  ISMEAR =  0  broad. in eV, -4-tet -1-fermi 0-gaus



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