Parameterization of the IEF PCM model for calculating solvation energies in N-methylpyrrolidone solution

Theoretical modelling of N-methylpyrrolidone (NMP) solutions, using a polarisable continuum model (IEFPCM), has been carried out with the aim to find the optimal value of a model parameter, a so-called scaling factor (alpha) for NMP, which should afford an improved modelling of various N-methylpyrrolidone solutions. Our working protocol comprised evaluations of the Gibbs free energy for the dissociation reaction of a set of 22 acids, employing the B2PLYP-D2/6-311+G**//B3LYP/6-31+G* approach, which were then used to calculate the acidity indices by considering the solvation energy at various values of alpha within the IEFPCM model. The optimal value of alpha for the N-methylpyrrolidone solvent has been found to amount to 1.40.