### Property Selection Options

#### EFG

Specifies that potential, field and field gradient are to be computed. This is the default.

#### Potential

Specifies that the potential but not the field or field gradient are to be computed. NoPotential suppresses computation of the electric potential and higher properties.

#### Field

Specifies that the potential and field, but not the field gradient, are to be computed.

#### EPR

Compute the anisotropic hyperfine coupling constants (i.e., spin-dipole EPR terms) [Barone96, Rega96, Barone96a].

### Input Source-Related Options

If both Read and Opt are specified, the order of the input sections is fixed points (Read), then optimized points (Opt).

#### Read

Causes the program to read a list of additional centers at which properties will be computed from the input stream. The Cartesian coordinates of each center in angstroms are read in free field, with one center per line, in the standard orientation.

#### Opt

Causes the program to read a list of centers as in Prop=Read, but then to locate the minimum in the electric potential closest to each specified point.

#### FitCharge

Fit atomic charges to the electrostatic potential at the van der Waals surface.

#### Dipole

Constrain fitted charges to the dipole moment.

#### Grid

Specifies that the potential is to be calculated at one or more grids of points and written to an external file (generally superseded by the cubegen utility). This option requests mapping of the electric potential over a 2D grid of points. The points can be specified as a uniform rectangular grid, as an arbitrary collection read from an auxiliary file (both described below), or via the input format used by cubegen.

Three additional input lines are required for a uniform grid:

KTape,XO,YO,ZO |
Fortran unit for write, coords. of map's lower left corner. |

N1,X1,Y1,Z1 |
# grid rows & vertical step size. |

N2,X2,Y2,Z2 |
# grid column & horizontal step size. |

For points read from an auxiliary file, a single line of input supplies all of the necessary information:

N,NEFG,LTape,KTape

The coordinates of N points in Angstroms will be read from unit LTape, in format 3F20.12. LTape defaults to 52. The potential (NEFG=3), potential and field (NEFG=2), or potential, field, and field gradient (NEFG=1) will be computed and written to unit KTape. For example, the following input indicates that 19,696 points for the electrostatic potential (code 3) will be read from Fortran unit 10, with output written to Fortran unit 11:

19696,3,10,11

HF, all DFT methods, CIS, TD, MP2, MP3, MP4(SDQ), CID, CISD, CCD, CCSD, and QCISD.