This directive
is only use by a four-body run.
Operand
types |
I |
F |
I |
I |
Operand
names |
ILABEL |
K4 |
S |
N |
ILABEL is an integer
label giving the index of the four-body bond type. The same label is
used in the TORS directive. ILABEL must
be 1 for the first four-body bond type, 2 for the second, and so on
up to a maximum of MAXTOR. The analytic form of the potential is
where is
the torsion angle in the crystal.
is in eV. s is ±1.0. N is an integer which gives
the periodicity of the torsion.