10.1021/jp107557p.s001 Debashree Ghosh Debashree Ghosh Dmytro Kosenkov Dmytro Kosenkov Vitalii Vanovschi Vitalii Vanovschi Christopher F. Williams Christopher F. Williams John M. Herbert John M. Herbert Mark S. Gordon Mark S. Gordon Michael W. Schmidt Michael W. Schmidt Lyudmila V. Slipchenko Lyudmila V. Slipchenko Anna I. Krylov Anna I. Krylov Noncovalent Interactions in Extended Systems Described by the Effective Fragment Potential Method: Theory and Application to Nucleobase Oligomers American Chemical Society 2010 structure package DNA strands Noncovalent Interactions Effective Fragment Extended Systems Described EFP method Pairwise fragment interactions interaction energy dimer binding energies component oligomer energy acid bases ab initio calculations Nucleobase OligomersThe implementation dispersion energy 2010-12-09 00:00:00 Journal contribution https://acs.figshare.com/articles/journal_contribution/Noncovalent_Interactions_in_Extended_Systems_Described_by_the_Effective_Fragment_Potential_Method_Theory_and_Application_to_Nucleobase_Oligomers/2706241 The implementation of the effective fragment potential (EFP) method within the Q-CHEM electronic structure package is presented. The EFP method is used to study noncovalent π−π and hydrogen-bonding interactions in DNA strands. Since EFP is a computationally inexpensive alternative to high-level ab initio calculations, it is possible to go beyond the dimers of nucleic acid bases and to investigate the asymptotic behavior of different components of the total interaction energy. The calculations demonstrated that the dispersion energy is a leading component in π-stacked oligomers of all sizes. Exchange-repulsion energy also plays an important role. The contribution of polarization is small in these systems, whereas the magnitude of electrostatics varies. Pairwise fragment interactions (i.e., the sum of dimer binding energies) were found to be a good approximation for the oligomer energy.