EWALD ARTIFACTS IN LIQUID-STATE MOLECULAR-DYNAMICS SIMULATIONS

An investigation into the effects of the anisotropic nature of the Ewa ld potential for the treatment of long range electrostatic interaction s in liquid solutions has been performed. The rotational potential ene rgy surface for two simple charge distributions, and a small protein, have been studied under conditions typically implemented in current bi omolecular simulations. A transition between hindered and free rotatio n is observed which can be modeled quantitatively for simple charge di stributions. For most systems in aqueous solution, the transition invo lves an energy change well below k(B)T. It is argued that, for solvent s with a reasonably high relative permittivity Ewald artifacts will be small and in many cases may be safely ignored. (C) 1996 American Inst itute of Physics.