Isotope Effects in Water: Differences of Structure, Dynamics, Spectrum, and Proton Transport between Heavy and Light Water from ReaxFF Reactive Force Field Simulations

Abstract

Investigating properties of both heavy and light water at the atomistic level is essential to understanding chemical and biological processes in aqueous solution. However, appropriately describing their difference on the nanoscale is still challenging. Employing ReaxFF reactive molecular dynamics simulations, we systematically study the structure, dynamics, and spectra of heavy and light water. With the water force field potential we developed, the different features between heavy and light water can be simulated appropriately by the classical treatment on large size and time scale. Here, we also report the structural difference between DO and HO in bulk heavy/light water. In addition, the diffusion constants of heavy and light water are successfully reproduced, and the Grotthuss hopping mechanism of proton transport in liquid water is properly described as well. It allows us to study a complex system in heavy/light aqueous environments, such as proton transport, chemical reaction, and tracing the reaction mechanism with an isotope substitute.

Searching for correlations between vibrational spectral features and structural parameters of silicate glass network

“…It is well‐known that glass properties simulated with MD can vary depending on the choice of potential functions describing interatomic interactions . Because the prime interest of this study is spectral features and the IR spectrum can be obtained from the autocorrelation of polarization fluctuations of the simulated structure, we compared the SR‐IR spectra calculated with different potentials with the experimental spectra shown in Figure A to choose the most appropriate one for further in‐depth analysis. At this moment, obtaining the Raman spectrum from MD‐simulated structures is quite difficult, so we did not use the Raman spectra in Figure B for comparison.…”

“…,35,72 we compared the SR-IR spectra calculated with different potentials with the experimental spectra…”

Recent advances in quantum‐mechanical molecular dynamics simulations of proton transfer mechanism in various water‐based environments

“…The RFF potentials specifically adjusted to study hydrated protons have been developed and applied to MD simulation of an excess proton in a water system. [18][19][20][21][22][23][24] Among the RFF approaches, the most popular method for revealing mechanistic details and elucidating structural and dynamical properties of the PT process is the multiple empirical valence bond (MS-EVB). [25][26][27] The application of MS-EVB to examine proton dynamics has been investigated in diverse model systems ranging from H 3 O + 28-45 and OH − 41,46 diffusion in bulk water, water-ice interface, 47 and confined water environment [48][49][50] to metal surfaces.…”

“…The parameterized reactive force field (RFF) is one of the practical approaches for describing chemical reactions in large molecular systems. The RFF potentials specifically adjusted to study hydrated protons have been developed and applied to MD simulation of an excess proton in a water system . Among the RFF approaches, the most popular method for revealing mechanistic details and elucidating structural and dynamical properties of the PT process is the multiple empirical valence bond (MS‐EVB) .…”

Ion-Specific Effects on Hydrogen Bond Network at a Submicropore Confined Liquid-Vacuum Interface: An in Situ Liquid ToF-SIMS Study

“…This might be due to the fact that D 2 O is more strongly structured (deuterium-bonded) than H 2 O. Thus, the water clusters in D 2 O are more stable than in H 2 O. , …”