On the Effects of Changing Gaussian Program Version and SCRF Defining Parameters: Isopropylamine as a Case Study

The present study reports a performance evaluation of the new Gaussian program version G09 relatively to the previous one in what concerns the SCRF formalism. The potential improvements achieved by changing program version and other SCRF defining parameters (like radii and SCRF models) were evaluated, by comparing the predicted values of several molecular properties with the corresponding experimental values reported in the literature. The relevance of the dispersion effects in the prediction of those molecular properties was inferred by considering the G09 newly implemented B97D DFT. On the whole, the results showed that the precision achieved in the molecular properties prediction is strongly dependent on the choice of the computation defining parameters. Moreover, direct comparisons between results obtained using either G03 or G09 require precaution.