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arXiv · 1808.10270

Nuclear Quantum Effects on the Vibrational Dynamics of Liquid Water

Deepak Ojha·Andres Henao·Thomas D Kühne
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Abstract

Based on quantum-mechanical path-integral molecular dynamics simulations the impact of nuclear quantum effects on the vibrational and hydrogen bond dynamics in liquid water is investigated. The instantaneous fluctuations in the frequencies of the O-H stretch modes are calculated using the wavelet method of time series analysis, while the time scales of the vibrational spectral diffusion are determined from frequency-time correlation functions, joint probability distributions, as well as the slope of three-pulse photon echo. We find that the inclusion of nuclear quantum effects leads not only to a redshift of the vibrational frequency distribution by around 130~cm$^{-1}$, but also to an acceleration of the vibrational dynamics by as much as 30$\%$. In addition, quantum fluctuations also entail a significantly faster decay of correlation in the initial diffusive regime, which is agreement with recent vibrational echo experiments.

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Deepak Ojha, Andres Henao, Thomas D Kühne. 2018-08-30. Nuclear Quantum Effects on the Vibrational Dynamics of Liquid Water. https://doi.org/10.1063/1.5005500

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