DL_POLY_2 can use either the Ewald method or direct summation to
calculate the electrostatic potentials and forces in periodic (or
pseudo-periodic) systems. For non-periodic systems only direct
summation is possible. If the Ewald summation is requested (with the
ewald sum or ewald precision directives in the CONTROL file) without periodic boundary
conditions, termination of the program results.
Action:
Select periodic boundaries by setting the variable imcon
0 in
the CONFIG file (if possible) or use a different method to evaluate electrostatic interactions
e.g. by usinf the coul directive in the CONTROL file.