The '''Effectiveeffective Fragmentfragment Potentialpotential (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|bibcode=2001JPCA..105..293G |url=https://lib.dr.lib.iastate.edu/cgibitstreams/viewcontent.cgi?article=1392&context=chem_pubs9bb4a991-d634-4b3c-93d3-7ae7612d9390/download}}</ref> It is a computationally inexpensive means to describe interactions in non-bonded systems.<ref>{{Cite web|url=https://libefp.github.io|title=libefp: The Effective Fragment Potential method|website=libefp.github.io|access-date=2017-11-15}}</ref><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 book|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|publisher=Elsevier|doi=10.1016/S1574-1400(07)03010-1|isbn=9780444530882}}</ref> However,But it has undergone vast improvements in the past two decades, and is currently used to represent intermolecular interactions (represented as rigid fragments), and in [[Molecularmolecular Dynamicsdynamics]] (MD) simulations as well.<ref name="MSG paper"/>
