Q-Chem 4.3 User’s Manual

3.15 Applying a Multipole Field ($multipole_field)

Q-Chem has the capability to apply a multipole field to the molecule under investigation. Q-Chem scans the input deck for the $multipole_field keyword, and reads each line (up to the terminator keyword, $end) as a single component of the applied field.

Example 3.17  General format for imposing a multipole field.

   field_component_1   value_1
   field_component_2   value_2

The field_component is simply stipulated using the Cartesian representation e.g. X, Y, Z, (dipole), XX, XY, YY (quadrupole) XXX, etc., and the value or size of the imposed field is in atomic units.