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7 The INCAR File



 SYSTEM = Rhodium surface calculation

 Start parameter for this Run:
   ISTART =      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 
   IALGO  =     18    algorithm   NELM   =     60;   NELMIN= 0; NELMDL=  3    # of ELM steps m
   EDIFF  =   1E-04   stopping-criterion for ELM      
   BMIX = 2.0 
   TIME = 0.05

 Ionic Relaxation
   EDIFFG =  .1E-02   stopping-criterion for IOM
   NSW    =       9   number of steps for IOM
   IBRION = 2         

   POTIM  =   10.0    time-step for ion-motion

   POMASS = 102.91
   ZVAL   =   11.0

 DOS related values:
   SIGMA  =    0.4;  ISMEAR =  1  broad. in eV, -4-tet -1-fermi 0-gaus

Table 2: The INCAR file for a Copper surface calculation.

INCAR is the central input file of VASP. It determines 'what to do and how to do it', and contains a relatively large number of parameters. 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 backlash 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.

A typical (relative complex) INCAR is given in Tab 2. The following sections will describe the parameters given in the INCAR file.

Especially the initialization of all things might be a little bit complicated, please read the section 7.15 carefully; it gives some hints how the initialization parameters interact, and how they might be used together.

Mon Mar 29 10:38:29 MEST 1999