Keywords for System Specification

General information defining the molecular system: nuclear coordinates, symmetry, basis functions, number of occupied MOs, etc. which are required by every module.

$title

give title of run or project here.

$symmetry d4h

Schönflies symbol of the point group. All point groups are supported with the exception of NMR shielding and force constant calculations etc. which do not work for groups with complex irreps (C₃, C₃h, T, etc). Use a lower symmetry group in this case.

$atoms

Example:

 
$atoms
cu 1-4                                                             \
   basis =cu ecp-18 arep                                           \
   jbas  =cu ecp-18                                                \
   ecp   =cu ecp-18 arep
se 5-6                                                             \
   basis =se ecp-28 arep dzp                                       \
   jbas  =se ecp-28                                                \
   ecp   =se arep

note the backslash \ : this is necessary. For each type of atom, one has to specify

-

the basis set

-

and the auxiliary (fitting) basis for RIDFT calculations

-

the ECP if this is used.

The files basis, ecp and jbas must provide the necessary information under the labels specified in $atoms.

$pople char

This data group specifies the number of cartesian components of basis functions (i.e. 5d and 7f in AO-Basis, 6d and 10f in CAO-Basis) for which the SCF calculation should be performed. Possible values for char are AO (default) or CAO. If CAO is used--which is not recommended--a core guess must be used instead of a Hückel guess (see $scfmo).