Hallo,

I have a problem with the Ewald summation. If I use it in the Forcite Tool (for example for the electrostatic terms) there is an warning in the output. I did not understand what the problem is. Here the part of the output (in this case only a energy calculation, no optimization):

Forcefield                      : Dreiding
Electrostatic terms:
  Summation method              : Ewald
  Accuracy                      : 0.001 kcal/mol
  Buffer width                  : 0.5 A

van der Waals terms:
  Summation method              : Atom based
  Truncation method             : Cubic spline
  Cutoff distance               : 8.5 A
  Spline width                  : 1 A
  Buffer width                  : 0.5 A

Hydrogen bond terms:
  Summation method              : Atom based
  Truncation method             : Cubic spline
  Cutoff distance               : 4.5 A
  Spline width                  : 0.5 A
  Buffer width                  : 0.5 A

---- Current structure ----
Warning. An Ewald summation has been chosen for the electrostatic terms. The current
implementation assumes that all interactions are of the form F(1/Rij), but the forcefield
contains other terms.
They will all be treated as F(1/Rij).

What terms of the forcefield is mean here? Is it a problem that the form F(1/Rij) is treated? What does this warning mean?

Thank you