The input of deMon2k is easy and mnemonic and at the same time offers high
flexibility. The input file contains keywords, options and keyword bodies.
A keyword together with its options, and the keyword body forms a keyword
block. The ordering of these blocks is free. The keyword body starts in
a new input line directly after the keyword line(s), and must have the
appropriate structure given in Chapter 4. All keywords, with
the exception of GEOMETRY or its equivalent, REACTANT and PRODUCT, have
associated default values which are used if the keyword is not explicitly
specified in the input. Thus, the simplest deMon2k input contains only
the coordinates of the atoms in the molecule to be calculated in the
keyword body of GEOMETRY. deMon2k uses special symbols to make the keyword
input flexible and efficient. Table 3 summarizes the special
symbols that are allowed in the job input file deMon.inp.
Special symbols of the deMon
|Symbol || Description |
& || Continuation of a keyword line |
# || First character of a comment line |
= || Assignment of numerical values to options |
|| Mathematical greater than symbol |
|| Mathematical smaller than symbol |
^|| Mathematical power symbol |
- || Combination of keyword options |
Space || Separation of keyword and options |
, || Separation of different options (optional) |
END || End of a keyword data block |
Lines in the job input file deMon.inp are restricted to
80 characters. The input is not case sensitive. A keyword line can be continued
by the & symbol at the very end of the line. At most, five continuation
lines are permitted. The lines in the keyword body cannot be continued and,
therefore, are limited to 80 characters. The TITLE line also cannot be
continued and the length of the title string is restricted to 60 characters.
The symbol # indicates a comment line. Comment lines can occur only
between complete keyword blocks including the keyword body, if it exists
(Placing comments inside a keyword line or body results in unpredictable read
operations). The end of a keyword block can be indicated by an END
statement, by a comment symbol # in a new input line, or simply by a
new keyword line.
Keyword options must be given directly after the keyword, separated by
space(s). If options are not present, the default settings for them
are used. Numerical values are assigned by the = sign to keyword options
(e.g. SCFTYPE Tol = <Real>, where <Real> indicates a real
number). The - sign is reserved for combining keyword options
(e.g. VXCTYPE B88-LYP) where that is allowed. The other mathematical
symbols in Table 3 are used according to their mathematical meaning.
They can be surrounded by space(s).