Two-dimensional infrared spectroscopy of aqueous solutions from first principles simulations

Abstract

Vibrational spectral diffusion of OH/OD modes in liquid water can be influenced by the presence of ions, dipolar solutes or by the change of temperature. In the present work, we have calculated the two-dimensional infrared (2D-IR) spectrum of aqueous NaBr and urea solutions at room temperature and also liquid water at two different temperatures to study the effects of these solutes and varying temperature on the dynamics of vibrational spectral diffusion of OD stretch modes in aqueous media. Time-dependent evolution of the ellipticity of 2D-IR spectra is calculated to obtain timescales of the dynamics of vibrational spectral diffusion.