Ion-mediated hydrogen-bond rearrangement through tunnelling in the iodide–dihydrate complex

Abstract

A microscopic picture of hydrogen-bond structure and dynamics in ion hydration shells remains elusive. Small ion-dihydrate molecular complexes represent ideal systems to investigate the interplay and competition between ion-water and water-water interactions. Here, state-of-the-art quantum dynamics simulations provide evidence for tunneling in hydrogenbond rearrangements in the iodide-dihydrate complex and show that it can be controlled through isotopic substitutions. We find that the iodide ion weakens the neighboring waterwater hydrogen bond, leading to faster water reorientation than in the analogous water trimer. These faster dynamics, which are apparently at odds with the slowdown observed in the first hydration shell of iodide in solution, can be traced back to the presence of a free OH bond in the iodide-dihydrate complex, which effectively triggers the overall structural rearrangements within it. Besides providing indirect support for co-operative hydrogen-

Calculations of quantum tunnelling rates for muonium reactions with methane, ethane and propane

“…25,26 It has been successfully applied to study quantum tunnelling in a wide variety of chemical processes. 5,[8][9][10]23,[27][28][29][30][31][32][33][34][35][36][37][38][39] The instanton is defined as the optimal tunnelling pathway which traverses the barrier region. This pathway is found using a discretisation into N ring-polymer beads and by locating a saddlepoint on the resulting effective ring-polymer potential-energy surface.…”

Hydrogen-bonded host–guest systems are stable in ionic liquids

“…However, we note that this work is just another piece towards completion of a very complicated puzzle. Further, and hopefully combined, experimental and theoretical developments 42 – 48 will be required before the nature of noncovalent interactions can be fully elucidated.…”

Data-Driven Many-Body Models with Chemical Accuracy for CH4/H2O Mixtures

“…1 to develop TTM-nrg and MB-nrg PEFs for halide-water, 82,83 alkali-metal ion-water, 84,85 and carbon dioxide-water systems, 86 which have been employed in computer simulations of various aqueous systems. [94][95][96][97][98][99][100][101] While both TTM-nrg and MB-nrg PEFs rely on MB-pol to describe water-water interactions, they differ in the functional forms adopted to represent solute distortions and solute-water interactions. In the TTM-nrg PEF, the CH 4 1B term is represented by a functional form similar to those used in common force fields, which is expressed in Eq.…”