Journal of Physical Chemistry B, Vol.119, No.29, 9312-9318, 2015
Classical Description of the Vibrational Spectroscopy, Structure, and Electrostatics of the Halide Solvation Shell with the POLIR Potential
POLIR (POLarizable for IR) (J. Chem. Phys. 2008, 129, 034504) is a polarizable, flexible, and transferable water potential which describes the IR spectrum in the O-H stretch region via the classical dipole correlation function with simple quantum corrections. POLIR also reproduces experimental spectral shifts in solutions of Ca2+, Mg2+, and Cu2+ (J. Am. Chem. Soc. 2011, 133, 9441-9450). Here we present an extended investigation of POLIR water in the solvation shell of the halides F-, Cl-, Br-, and I- using various interaction potentials, polarizabilities, and short-range electrostatic damping parameters. Our results indicate that the correlation of the first solvation shell dipoles produces IR spectra that are in agreement with experiment; that is, vibrational spectral shifts may be obtained with classical mechanics and simple corrections. Calculated ion induced dipoles agree with quantum simulations. Further analysis shows that ion-dependent shifts in the spectra may be attributed to the hydrogen bond O center dot center dot center dot O-H angle distribution within the first solvation shell, decomposed into ion-water and water-water contributions.