Water Clusters (Кластерная структура)

  • Water Clusters: The Real Truth About Water Molecules

    Chemists have long recognized water as a substance having unusual and unique properties that one would not at first sight expect from a small molecule having the formula H2O. It is generally agreed that the special properties of water stem from the tendency of its molecules to associate, forming short-lived and ever-changing polymeric units that are sometimes described as "clusters". These clusters are more conceptual than physical in nature; they have no directly observable properties, and their transient existence (on the order of picoseconds) does not support an earlier view that water is a mixture of polymers (H2O)n in which n can have a variety of values. Instead, the currently favored model of water is one of a loosely connected network that might best be described as one huge "cluster" whose internal connections are continually undergoing rearrangement.

    Water has long been known to exhibit many physical properties that distinguish it from other small molecules of comparable mass. Chemists refer to these as the "anomalous" properties of water, but they are by no means mysterious; all are entirely predictable consequences of the way the size and nuclear charge of the oxygen atom conspire to distort the electronic charge clouds of the atoms of other elements when these are chemically bonded to the oxygen. 

  • Surface States of Excess Electrons on Water Clusters

    Electron attachment of water clusters was explored by the quantum path-integral molecular-dynamics method, demonstrating that the energetically favored localization mode involves a surface state of the excess electron. The cluster size dependence, the energetics, and the charge distribution of these novel electron-cluster surface states are explored.Most studies1 of small clusters focus on the dependence of the geometry, level structure, and other properties upon size (number of particles) and the "transition" from molecular to condensed-matter behavior. Characteristic to these systems is a large surface-to-volume ratio which could lead to unique, qualitatively different from bulk, chemical and physical behavior.2'3 In this Letter we shall demonstrate, using quantum path-integral molecular-dynamics simulations3'4 (QPIMD), that the energetically stable excess-electron states in small water clusters5"7 involve surface states rather than internally localized states which may be regarded as precursors of the celebrated hydrated electron.
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  • Structure and stability of spiro-cyclic water clusters

    Abstract. The structure and stability of spiro-cyclic water clusters containing up to 32 water molecules

    have been investigated at different levels of theory. Although there exist minima lower in energy than
    these spiro-cyclic clusters, calculations at the Hartree–Fock level, density functional theory using B3LYP
    parametrization and second order Møller–Plesset perturbation theory using 6-31G and 6-311++G
    basis sets show that they are stable in their own right. Vibrational frequency calculations and atoms-in
    molecules analysis of the electron density map confirm the robustness of these hydrogen bonded clusters.

    Keywords. Hydrogen bonding; water clusters; spiro-cyclic; atoms-in-molecules.

  • Benefits of Alkaline, Ionized Water

    Сверионизированная вода - это вода, получаемая в процессе электролиза воды. Она имеет щёлочную реакцию, её ОВП снижается, уменьшается поверхностное натяжение, снижается количество растворённого кислорода и азота, возрастает концентрация водорода, свободных гидроксильных групп, уменьшается электропроводность, изменяется структура не только гидратных оболочек ионов, но и свободного объёма воды. Такая вода нейтрализует повышенную кислотность организма.

  • Electronic Structure of Ionized Water Clusters

    Eric J. Sundstrom, Piotr A. Pieniazek, and Anna I. Krylov

    Ionization of liquid water is of great practical interest in the context of atmospheric and biological chemistry. The removal of an electron leads to cascade formation of reactive intermediates that can incur cellular damage. Despite several decades of research the nature of the initially formed state and its immediate dynamics are still poorly understood. We pose a very fundamental question: "What does it mean to ionize water?"

  • Infrared cavity ringdown spectroscopy of water clusters: O– D stretching bands

    The infrared O – D stretching spectrum of fully deuterated jet-cooled water clusters is reported.
    Sequential red-shifts in the single donor O – D stretches, which characterize the cooperative effects
    in the hydrogen bond network, were accurately measured for clusters up to ( D2O) 8 . Detailed
    comparisons with corresponding data obtained for ( H2O) n clusters are presented. Additionally,
    rotational analyses of two D2O dimer bands are presented. These measurements were made possible
    by the advent of infrared cavity ringdown laser absorption spectroscopy IR-CRLAS using
    Raman-shifted pulsed dye lasers, which creates many new opportunities for gas phase IR
    spectroscopy.

  • “Water Buckyball” Terahertz Vibrations in Physics, Chemistry, Biology, and Cosmology

    Pentagonal dodecahedral water clusters – “water buckyballs” - and arrays thereof are shown from

    first-principles electronic-structure calculations to possess unique terahertz-frequency vibrational
    modes in the 1-6 THz range, corresponding to O–O–O “bending”, “squashing”, and “twisting”
    “surface” distortions of the clusters. The cluster LUMOs are huge “Rydberg” “S”-, “P”-, “D”-, and
    “F”like molecular orbitals that accept an extra electron via optical excitation, ionization, or
    electron-donation from interacting atoms or molecules.

  • Hydrogen-Bond Networks in Water Clusters (H2O)20: An Exhaustive Quantum-Chemical

    Water aggregates allow for numerous configurations due to different
    distributions of hydrogen bonds. The total number of possible
    hydrogen-bond networks is very large even for medium-sized
    systems. We demonstrate that the targeted ultra-fast methods of
    quantum chemistry make an exhaustive analysis of all configurations
    possible. The cage of (H2O)20 in the form of the pentagonal
    dodecahedron is a common motif in water structures. We calculated
    the spatial and electronic structure of all hydrogen-bond
    configurations for three systems: idealized cage (H2O)20 and defect
    cages with one or two hydrogen bonds broken. More than 3 million
    configurations studied provide unique data on the structure and
    properties of water clusters. We performed a thorough analysis of the
    results with the emphasis on the cooperativity in water systems and
    the structure-property relations.

  • Untangling the mysteries of the liquid. Научные доказательства кластерной структуры воды

    В этом разделе собраны иинтересные научные статьи по структуре воды, написанные зарубежными учёными (на русском языке таких материалов или очень мало, или нет вообще). Все эти статьи я с большим трудом отыскал в интернете и скачал с сайтов зарубежных научных журналов. Эти материалы действительно уникальны по своей научной значимости, поскольку их результаты доказывают кластерную структуру воды. Материалы уникальные тем, что это полные статьи. Обычно научные журналы не публикуют полнотекстные статьи, а дают лишь короткую аннотацию. Поэтому найти полноценные научные статьи в интернете довольно сложно. Нужно либо идти в научную библиотеку или платить деньги интернет-редакциям. Поэтому это будет очень полезно нашим читателям и особенно людям, работающей в научной сфере, так как таких статей на русском языке практически нет. Меня очень часто читатели спрашивают тот или иной физико-химический показатель, а здесь все они собраны воедино.
    Мосин Олег