Density Functional Theory (DFT) is one of the most widely used methods for “ab initio” calculations of the structure of atoms, molecules crystal, surfaces and their interactions. In this study we have composed experimental bond distances of a set of molecules C2H2, C2H4, C2H6, HCN, NH3. O3, Li2, H2, H2O HF, BH, H2CO, and N2H4 obtained from electron paramagnetic resonance (EPR) spectroscopy with the corresponding bond distances of the same molecule obtained from DFT functionals, local spin density approximation LSDA, and BLYP. The accuracy of DFT functionals LSDA and BLYP is investigated via statistical analysis of the error. We have found that the bond distances of the molecules obtained from the BLYP functionals are closer to the experimentally observed bond distances in comparison of the bond distances obtained from LSDA functionals are not recommended for calculation of the bond distances of the molecules
Keywords: Density functional theory, electron paramagnetic resonance, bond, functional etc.