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Water cluster
About: Water cluster is a research topic. Over the lifetime, 1430 publications have been published within this topic receiving 34840 citations.
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TL;DR: A consistent approach is derived for predicting the solvation free energies of charged solutes in the presence of implicit and explicit solvents because of the incorrect accounting of the standard state corrections for water molecules or water clusters present in the thermodynamic cycle.
Abstract: We derive a consistent approach for predicting the solvation free energies of charged solutes in the presence of implicit and explicit solvents. We find that some published methodologies make systematic errors in the computed free energies because of the incorrect accounting of the standard state corrections for water molecules or water clusters present in the thermodynamic cycle. This problem can be avoided by using the same standard state for each species involved in the reaction under consideration. We analyze two different thermodynamic cycles for calculating the solvation free energies of ionic solutes: (1) the cluster cycle with an n water cluster as a reagent and (2) the monomer cycle with n distinct water molecules as reagents. The use of the cluster cycle gives solvation free energies that are in excellent agreement with the experimental values obtained from studies of ion−water clusters. The mean absolute errors are 0.8 kcal/mol for H+ and 2.0 kcal/mol for Cu2+. Conversely, calculations using th...
541 citations
TL;DR: The precise arrangement of water molecules in the protein matrix results in a controlled Grotthuss proton transfer, in contrast to the random proton migration that occurs in liquid water, support the emerging paradigm that intraprotein water molecules are as essential for biological functions as amino acids.
Abstract: Much progress has been made in our understanding of water molecule reactions on surfaces, proton solvation in gas-phase water clusters and proton transfer through liquids. Compared with our advanced understanding of these physico-chemical systems, much less is known about individual water molecules and their cooperative behaviour in heterogeneous proteins during enzymatic reactions. Here we use time-resolved Fourier transform infrared spectroscopy (trFTIR) and in situ H2(18)O/H2(16)O exchange FTIR to determine how the membrane protein bacteriorhodopsin uses the interplay among strongly hydrogen-bonded water molecules, a water molecule with a dangling hydroxyl group and a protonated water cluster to transfer protons. The precise arrangement of water molecules in the protein matrix results in a controlled Grotthuss proton transfer, in contrast to the random proton migration that occurs in liquid water. Our findings support the emerging paradigm that intraprotein water molecules are as essential for biological functions as amino acids.
501 citations
TL;DR: In this article, the authors used photoelectron imaging to characterize a class of (H2O)n− and (D2On−)n-cluster anions with vertical binding energies that are significantly lower than those previously recorded.
Abstract: Anionic water clusters have long been studied to infer properties of the bulk hydrated electron. We used photoelectron imaging to characterize a class of (H2O)n– and (D2O)n– cluster anions (n ≤ 200 molecules) with vertical binding energies that are significantly lower than those previously recorded. The data are consistent with a structure in which the excess electron is bound to the surface of the cluster. This result implies that the excess electron in previously observed water-cluster anions, with higher vertical binding energies, was internally solvated. Thus, the properties of those clusters could be extrapolated to those of the bulk hydrated electron.
368 citations
TL;DR: It is reported that broadband rotational spectroscopy in a pulsed supersonic expansion unambiguously identifies all three isomers of the water hexamer; their oxygen framework structures are determined by means of oxygen-18–substituted water (H218O).
Abstract: Theory predicts the water hexamer to be the smallest water cluster with a three-dimensional hydrogen-bonding network as its minimum energy structure. There are several possible low-energy isomers, and calculations with different methods and basis sets assign them different relative stabilities. Previous experimental work has provided evidence for the cage, book, and cyclic isomers, but no experiment has identified multiple coexisting structures. Here, we report that broadband rotational spectroscopy in a pulsed supersonic expansion unambiguously identifies all three isomers; we determined their oxygen framework structures by means of oxygen-18-substituted water (H(2)(18)O). Relative isomer populations at different expansion conditions establish that the cage isomer is the minimum energy structure. Rotational spectra consistent with predicted heptamer and nonamer structures have also been identified.
360 citations
TL;DR: In this paper, the experimental results on the effects of a magnetic field on water are reported, and the correlation time τ c was calculated in terms of spin-lattice relaxation time of proton NMR, which verified that the rotational motions got slow down after magnetic treatments.
336 citations