Includes a lattice of point charges, for use in QM/MM calculations for example (see section 59). An external file (input_file) should be given as input, with the following format:
number of point charges N
The and fields stand for the point charge coordinates (in Å), for its charge and flag=1 indicates that gradients should be computed for this lattice point (0 means no gradient).
outfile specifies a file name to which the lattice gradient is written; if blank, it will be written to the output stream.
Symmetry is not supported for lattice gradients.