EXTERNALS

The EXTERNALS block key controls the input data for the MM atoms. If this block is not found no DRF calculation will be performed. For each MM atom the following data are required:

EXTERNALS
 atm num grp-nam grp-num, char, x, y, x, pol
 ...
 GROUP
 {...}
end

atm

Type of atom, i.e., H, O, ...

num

number of atoms (optional)

grp-nam

Name of the group to which the atom belongs

grp-num

Number of the group to which the atom belong

char

atomic charge (in atomic units)

x

x-coordinate

y

y-coordinate

z

z-coordinate

pol

atomic polarizability (in atomic units)

GROUP

Indicates the end of group

The separation of molecules into GROUP's are important. Since in the many-body polarization operator only inter-molecular interactions, i.e. only interaction between sites which do not belong to the some group, are included. Therefore, it is important that the combined string (grp-nam + grp-num) is unique for each GROUP.

EXTERNALS
 O  4 water    2, -0.6690, -11.380487, -11.810553,  -4.515226,  9.3005
 H  5 water    2,  0.3345, -13.104751, -11.837669,  -3.969549,  0.0690
 H  6 water    2,  0.3345, -10.510898, -12.853311,  -3.320199,  0.0690
 GROUP
 O  7 water    3, -0.6690,  -1.116350,   9.119186,  -3.230948,  9.3005
 H  8 water    3,  0.3345,  -2.822714,   9.717033,  -3.180632,  0.0690
 H  9 water    3,  0.3345,  -0.123788,  10.538199,  -2.708607,  0.0690
 GROUP
 {...}
end