Editing Molecular dynamics (section)

== Long-range forces ==
A long range interaction is an interaction in which the spatial interaction falls off no faster than <math>r^{-d}</math> where <math>d</math> is the dimensionality of the system. Examples include charge-charge interactions between ions and dipole-dipole interactions between molecules. Modelling these forces presents quite a challenge as they are significant over a distance which may be larger than half the box length with simulations of many thousands of particles. Though one solution would be to significantly increase the size of the box length, this brute force approach is less than ideal as the simulation would become computationally very expensive. Spherically truncating the potential is also out of the question as unrealistic behaviour may be observed when the distance is close to the cut off distance.<ref>{{Cite book|title=Computer Simulation of Liquids| vauthors = Allen MP, Tildesley DJ |date=2017-08-22|publisher=Oxford University Press|isbn=9780198803201|edition= 2nd|pages=216|language=en|id={{ASIN|0198803206|country=uk}} }}</ref>