Basis set effects on the structure of isomeric nitroanilines: the role of basis set expansion, additional diffuse and polarization functions within the frame of DFT and MP2 approaches

Abstract

Influence of the basis set on the geometrical parameters and structural aromaticity indices of isomeric nitroanilines was studied in the framework of MP2 and DFT methods (M06-2X functional). Series of cc-pV(N)Z and def2-(N)ZVP basis sets of double-ζ, triple-ζ, and quadruple-ζ quality augmented with additional diffuse and/or polarization functions were investigated. It was found that using the basis sets of double-ζ quality can be the source of the significant error in MP2 calculations. Important role of additional diffuse functions and negligible influence of additional polarization functions was shown.