This type specifies the Sutton-Chen potential with periodic boundary
conditions (minimum image convention).
If no file named SCparams exists in the current
directory the 126 potential for gold is used. Otherwise the Sutton-Chen
and are read from this file in order. If the
keyword PRESSURE is set in the odata file
then a constant pressure optimisation is performed
with the energy being minimised by golden section with respect to the cubic box size before taking another
step. The cutoff is automatically changed in proportion to the change in box size.
Otherwise the optimisations are performed at constant volume, with no relaxation of the
unit cell. The bulk fcc nearest neighbour distance in the prevailing unit system is
Subroutines used: escp, dscp.