Frequency dependence of the reorientational motion of OD bonds of deuterated methanol in liquid phase: A first principles molecular dynamics study

Abstract

We present an ab initio molecular dynamics study of the frequency dependence of rotational motion of OD bonds of deuterated methanol in liquid phase. A time series analysis of the simulated trajectories is performed to calculate the fluctuating frequencies of the OD bonds and the frequency-resolved rotational dynamics are investigated through calculations of the first and second-rank rotational correlation functions of the OD bond vectors. The short-time dynamics is found to depend on the chosen frequency which, in turn, is related to different hydrogen bonded environments of methanol molecules. The long time dynamics is found to be independent of the frequency of OD bonds. The effects of dispersion interactions on the calculated results are also discussed. The current first principles results are compared with the available experiments on frequency dependence of rotational dynamics of similar alcoholic systems.