A Density Functional Theory Study of the Non-local Correlations between Nucleic Acid Base Pairs

The interactions of nucleic acid bases are fundamentally important in determining the behavior and structure of biologically important molecules such as DNA and RNA. However, the stacking of nucleic acid bases in a strand of genetic material involves significant van der Waals forces, which are often inaccurately represented or too expensive to compute in many modern theoretical methods. In this paper, we use Density Functional Theory (DFT) with a non-local van der Waals correlation functional\footnote{M. Dion, H. Rydberg, E. Schr\"{o}der, D.~C. Langreth and B.~I. Lundqvist, {Phys. Rev. Lett.} \textbf{{92}}, {24601-1} ({2004}).} to study the stacking interactions of nucleic acid base pairs. This method correctly and seamlessly accounts for the long-range interactions present among isolated fragments through a density-density interaction formula. Since this technique is implemented within DFT it has the advantage of being able to draw on the speed, efficiency and accuracy of this \emph{ab initio} method.