compass

Compass is used to do some preprocessing of the user's input. The main task of compass is to read molecule geometry and basis set and store them as internal data structure. The point group symmetry of molecule could be determined automatically and symmetry information will be generated.

General keywords

Basis

The following line is a string to specify the basis set name used in calculation. This string is used to locate the file in which basis set are stored. In general, there is a file with the name of capital "string" in the directory basis_library of BDF main directory. Except for the directory basis_library, the work directory will also be searched to locate the basis set. Thus, users can write the basis set into a file with the name of "NAME" in work directory and specify in input file.

Example:

$Compass
Basis
 cc-pvdz
$End

Geometry

The cartesian coordinates of a molecule are written as following lines with the format of

• Atom x y z

The string "End of geometry" is used to specify the end of the geometry input. The "xyz" formatted file can also be used as molecule geometry input. Users can write molecule geometry into a file named "geom.xyz" and put it in work directory. The compass will read molecule geometry from this file.

Example:

$Compas
Basis
  cc-pvdz
Geometry
  H  0.000   0.000    0.707
  H  0.000   0.000   -0.707
End of Geometry
$End

$Compass
Basis
  cc-pvdz
Geometry
  H2.xyz
End of Geometry
$End

Group

The following line is used to set the point group of the molecule used in calculation. Usually, the point group can be determined by BDF automatically. However, the point group with degenerated representation is only supported by BDF in HF/DFT/TDDFT calculations. In general, D2h and subgroup is used by most of BDF modules. By default, BDF will use highest ablian group of a molecules point group in calculation if use do not set "Skeleton" keyword. Users can specify the subgroup of molecule point group in calculation.

Examples: A linear molecule CO has the Cinfv linear symmetry. We can use highest albeilian subgroup in calculation

$Compass
Basis 
  sto-3g
Geometry
  C   0.0   0.0    0.0
  H   0.0   0.0    1.6
End of Geometry
Group
  C(2v)
$End

Expert keywords

Keyword3

xxx

Keyword4

xxx

Depend Files

Examples