12.6 Lattice of point charges

LATTICE,[INFILE=input_file,][OUTFILE=output_file,] [VARGRAD,][NUCONLY,][REMOVE]

Includes a lattice of point charges, for use in QM/MM calculations for example (see section 47). An external file (input_file) should be given as input, with the following format:

Comment line
number of point charges N
$x1,y1,z1,q1,$flag$1$

$xN,yN,zN,qN,$flag$N$

The $x, y$ and $z$ fields stand for the point charge coordinates (in Å), $q$ 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.

VARGRAD

(logical) Stores the lattice gradient in variable VARGRAD.

NUCONLY

(logical) Disables gradient evaluation with respect to the lattice, independent of flag in the lattice file.

REMOVE

(logical) Removes the lattice.

Symmetry is not supported for lattice gradients.