Hello,
This message is mainly intended for the MS developers. I have noticed that when computing ESP charges in periodic systems, the solution provided by Shyam is a script that removes the periodicity of the crystal, uses Dmol, etc, which turns out to be an approximation with limited applicability.
I have recently devised a simple, general and formal solution to the problem that the MS developers might find worth of checking. See:
J. Chem. Theory Comput., 2009, 5 (10), pp 2866–2878, DOI: 10.1021/ct9003405
Cheers,
Carlos Campana