Vibrational dynamics of liquid water in an external electric field.

Abstract

In our present study, we have investigated the effects of an externally applied static electric field on the vibrational dynamics of liquid water (D2O) using ab initio molecular dynamics. The rate of vibrational spectral diffusion is obtained from simulated two-dimensional infrared spectra, three-pulse photon echo intensity, and frequency correlation functions and distributions. We find that the static vibrational frequency distribution undergoes a redshift of 90 cm-1 whereas the overall vibrational dynamics get slower with the relaxation time constant to be around 4.9 ps. Thus we infer that the local hydrogen bond network tends to reorganize in the presence of an external field with an increase in local structural order as evident from the overall slower vibrational dynamics and reduced molar entropy.