Levels of theory modifications and their effects on 1JCH SSCCs calculations: A factorial design analysis

Two-level factorial design has been used to determine the effects of modifications of the level of theory on calculated 1JCH SSCCs of norbonane derivatives. We analyzed the effect of four factors: the method used in geometry optimization, the functional, the basis set, and the solvent in constant coupling calculations. Our results show that the coupling constant does not require the use of the MP2 method in geometry optimizations. Nevertheless, the interaction effect between the chosen functional and the basis set used in 1JCH SSCCs calculations is extremely important. The levels of theory selected were B3LYP/aug-cc-pVDZ, for geometry optimization, and B3LYP/EPR-III, for 1JCH SSCCs calculations, considering the molecule in gas phase. The chosen levels of theory showed a good agreement with experimental data.