The Effective Fragment Potential (EFP) method is a computational approach designed to describe intermolecular interactions and environmental effects.<ref name="MSG paper">{{cite journal|last1=Gordon|first1=Mark S.|last2=Freitag|first2=Mark A.|last3=Bandyopadhyay|first3=Pradipta|last4=Jensen|first4=Jan H.|last5=Kairys|first5=Visvaldas|last6=Stevens|first6=Walter J.|title=The Effective Fragment Potential Method: A QM-Based MM Approach to Modeling Environmental Effects in Chemistry|journal=The Journal of Physical Chemistry A|date=January 2001|volume=105|issue=2|pages=293–307|doi=10.1021/jp002747h}}</ref>. It is a computationally inexpensive means to describe interactions in non-bonded systems.<ref>{{cite web|title=Q-Chem 4.3 User’s Manual : Effective Fragment Potential Method|url=http://www.q-chem.com/qchem-website/manual/qchem43_manual/sect-efp.html|website=www.q-chem.com}}</ref>. It was originally formulated to describe the solvent effects in complex chemical systems.<ref>{{cite journal|last1=Gordon|first1=Mark S.|last2=Slipchenko|first2=Lyudmilla|last3=Li|first3=Hui|last4=Jensen|first4=Jan H.|title=Chapter 10 The Effective Fragment Potential: A General Method for Predicting Intermolecular Interactions|journal=Annual Reports in Computational Chemistry|date=1 January 2007|volume=3|pages=177–193|url=http://www.sciencedirect.com/science/article/pii/S1574140007030101|publisher=Elsevier}}</ref>. However, it has undergone vast improvements in the past two decades, and is currently used to represent intermolecular interactions (represented as rigid fragments), and in Molecular Dynamics (MD) simulations as well.<ref name="MSG paper"/>.
