Theoretical study on charge distribution in cetylpyridinium cationic surfactant

Here, we report the electrostatic potential maxima and partial atomic charges evaluated on cetylpyridinium cation. The Hartree-Fock method and six DFT functionals (namely, PBE, TPSS, B3LYP, PBE0, M06, and wB97) were used to calculate partial atomic charges via CHELPG, Mulliken, Lowdin, Hirshfeld, and natural population schemes. Calculations were performed for the gas phase and for the CPCM water solvated cation, resulting in a set of 70 types of partial atomic charges. The main tendencies in charge deviations were discussed. In comparison with the electrostatic potential-based CHELPG partial charges, Hirshfeld, Mulliken, Lowdin, and NPA partitioning schema lead to an almost steady decrease in the partial charges in the cetyl chain. This agreed closely with the redistribution of electrostatic potential mapped onto the 0.002 e/Bohr(3) isodensity surface.

Automated summary

In this study, the electrostatic potential maxima and partial atomic charges of cetylpyridinium cation were reported, with the main tendencies in charge deviations discussed. Different methods and functionals were used to calculate the partial atomic charges, leading to variations in charge distribution along the cetyl chain.