Assessment of split-charge equilibration model for development of polarizable force fields

Abstract

Performance of split-charge equilibration model (SQE) for force field development was tested by computing static and response characteristics of water clusters. Results of the study show that SQE yields reliable results for the molecular electrostatic potential, dipole, and polarizability of clusters of increasing size. Intermolecular charge transfer needs to be considered for hydrogen bonded systems in order to accurately reproduce the dipole versus system size behavior. It was found that the model quantitatively mimics the IR intensities of intermolecular vibrational modes, but fails in the computation of the IR and Raman intensities of intramolecular vibrations. The response of charge distribution to perturbation by point charge is confidently modeled by SQE in the conditions corresponding to the linear-response regime.