We have studied hydrogen bond dynamics in aqueous MgCl 2 solutions using the polarizable AMOEBA models for both water and the ions. We have investigated the timescales of both transients as well as true hydrogen bond‐breaking and reformation events. We also calculated the rate constants for both forward and backward hydrogen bond breaking and reformation events and investigated how these rate constants vary with changes in the salt concentration. The timescales of the forward process of hydrogen bond breaking are found to be longer for donor–acceptor water–anion pairs than donor–acceptor water–water hydrogen bonds. The residence time of a water molecule around a Cl − ion is found to be longer than that around another water molecule, which helps reformation of an initially broken Cl − ‐water hydrogen bond compared to that for a water–water pair. We also calculated the true hydrogen bond breaking timescale for donor–acceptor water–water pairs using coarse‐grained trajectories, ignoring the transient events, to further validate our findings of true hydrogen bond breaking and reformation kinetics. Our analysis shows that the strong electric field of the Mg 2+ ions contributes to the slowing down of the hydrogen bond dynamics in the solutions through induced polarization effects on surrounding water.
Vishwakarma et al. (Fri,) studied this question.