The INCAR File

**Table 1:** The INCAR file for a Copper surface calculation.
$\begin{table} \begin{verbatim}SYSTEM = Rhodium surface calculationStart pa... ... = 0.4; ISMEAR = 1 broad. in eV, -4-tet -1-fermi 0-gaus\end{verbatim}\end{table}$

INCAR is the central input file of VASP. It determines 'what to do and how to do it', and can contain 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 in dealing with 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. 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 (relatively complex) INCAR is given in Tab 1. 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 6.2 carefully; it gives some hints how the initialization parameters interact, and how they might be used together.