Temperature-dependent vibrational spectra and structure of liquid water from classical and quantum simulations with the MB-pol potential energy function

Abstract

The structure of liquid water as a function of temperature is investigated through the modeling of infrared and Raman spectra along with structural order parameters calculated from classical and quantum molecular dynamics simulations with the MB-pol many-body potential energy function. The magnitude of nuclear quantum effects is also monitored by comparing the vibrational spectra obtained from classical and centroid molecular dynamics, both in intensities and peak positions. The observed changes in spectral activities are shown to reflect changes in the underlying structure of the hydrogen-bond network and are found to be particularly sensitive to many-body effects in the representation of the electrostatic interactions. Overall, good agreement is found with the experimental spectra, which provides further evidence for the accuracy of MB-pol in predicting the properties of water.

A Two-State Picture of Water and the Funnel of Life

“…2d) with that ( Fig. 2c) obtained from simulations using the MB-pol force-field 36 , which includes up to three-body interactions fitted to a large set of structures computed at the quantum chemical gold-standard CCSD(T) level. The overall shift to lower frequencies with decreasing temperature is reproduced, but not the bimodality observed in experiment.…”

“…Recent developments with parameterization of up to three-body interactions at the CCSD(T) level of quantum chemical accuracy hold promise 30 , but the resulting structure is still unimodal, both in terms of computed XES 35 and Raman spectra (Fig. 2c) 36 . In another approach, VandeVondele and coworkers 31 135 and quantum ring-polymer contraction 136 .…”

“…35 . (c) Simulated H2O Raman spectrum using MB-pol 36 compared with (d) experiment [37][38] . Reprinted with permission from ref.…”

Chemical Accuracy in Modeling Halide Ion Hydration from Many-Body Representations

“…[92] for a recent review). Among existing many-body PEFs for water, MBpol has been shown to correctly predict the vibration-rotation tunneling spectrum of the water dimer [103], the energetics, quantum equilibria, and infrared spectra of small clusters [104,[106][107][108], the structural, thermodynamic, and dynamical properties of liquid water [105,109], the energetics of different ice phases [110], infrared and Raman spectra of liquid water [111][112][113], the vibrational sum-frequency generation spectrum of the air/water interface [114,115], the infrared and Raman spectra of ice I h [116]. More recently, molecular configurations extracted from classical (MD) and quantum pathintegral molecular dynamics (PIMD) simulations with MB-pol have been used to determine the electronic band gap of liquid water, both in the bulk and at the air/water interface, through many-body perturbation theory electronic structure calculations [117].…”

A first principles method to determine speciation of carbonates in supercritical water

“…We note that in our MD simulations, nuclei were treated as classical particles; the comparisons between intensities reported for the vibrational spectra of water with classical and quantum dynamics at ambient conditions do not show any qualitative difference and relatively small quantitative differences for the intensities, with blue-shifted frequencies of the order 60-120 cm −1 in the case of classical dynamics 33,34 . At elevated temperatures, we expect the small differences observed at ambient conditions to diminish.…”