Specifically, in the General Utility Lattice Program (GULP) 2003 paper, in the methods section on Two-body Short-range Interactions we have the following:
For covalently bonded atoms, it is often preferable to Coulomb subtract the interaction and to describe it with either a harmonic or Morse potential.
What exactly does that mean? Does that mean the Coulomb interaction has no effect at all when using a pair potential? That seems to be what it's implying to me, but I can't find an explanation of the terminology anywhere.