نتایج جستجو برای: water cluster

تعداد نتایج: 746887  

2005
K. L. Aplin

Results from previous laboratory experiments indicate that both the protonated water dimer H3O(H2O), and molecular cluster-ions, X(H2O)n absorb infra-red (IR) radiation in the water vapour continuum region between 4-14μm (2500-714cm). Protonated water clusters are a common species of atmospheric molecular cluster-ion, produced by cosmic rays throughout the troposphere and stratosphere. Under cl...

Journal: :Science 2005
László Turi Wen-Shyan Sheu Peter J Rossky

Water-cluster anions can serve as a bridge to understand the transition from gaseous species to the bulk hydrated electron. However, debate continues regarding how the excess electron is bound in (H2O)-n, as an interior, bulklike, or surface electronic state. To address the uncertainty, the properties of (H2O)-n clusters with 20 to 200 water molecules have been evaluated by mixed quantum-classi...

1998
Michael A. Johnson Eugene V. Stefanovich Thanh N. Truong Henry Eyring

We have applied a novel theoretical and computational method called CECILIA (combined embedded cluster at the interface with liquid approach) to study adsorption of molecular water on the MgO(001) surface and its interface with water. The MgO(001) surface is modeled by a quantum cluster embedded in a field of pseudopotentials and point charges. The effects of an aqueous environment are included...

Journal: :Current opinion in plant biology 2000
K L Westphal C Tommos R I Cukier G T Babcock

Photosystem II evolves oxygen by using water in the unlikely role of a reductant. The absorption of sunlight by chlorophyll produces highly oxidizing equivalents that are filled with electrons stripped from water. This proton-coupled redox chemistry occurs at the oxygen-evolving complex, which contains a tetramanganese cluster, a redox-active tyrosine amino acid hydrogen-bonded to a histidine a...

Journal: :The journal of physical chemistry. A 2006
Marco A Allodi Meghan E Dunn Jovan Livada Karl N Kirschner George C Shields

It has been speculated that the presence of OH(H2O)n clusters in the troposphere could have significant effects on the solar absorption balance and the reactivity of the hydroxyl radical. We have used the G3 and G3B3 model chemistries to model the structures and predict the frequencies of hydroxyl radical/water clusters containing one to five water molecules. The reaction between hydroxyl radic...

Journal: :Chemical communications 2014
Shan Wang Haolong Li Liying Zhang Bao Li Xiao Cao Guohua Zhang Shilin Zhang Lixin Wu

Surfactant-encapsulated polyoxometalate complexes are used as cluster suprasurfactants to transfer reduced graphene oxide (RGO) nanosheets from water to low polar organic solvents, which realizes the single-layer dispersion and the cluster-functionalization of RGO in one step.

Journal: :Dalton transactions 2011
Mohammad Mahdi Najafpour Govindjee

The Oxygen Evolving Complex in photosystem II, which is responsible for the oxidation of water to oxygen in plants, algae and cyanobacteria, contains a cluster of one calcium and four manganese atoms. This cluster serves as a model for the splitting of water by energy obtained from sunlight. The recent published data on the mechanism and the structure of photosystem II provide a detailed archit...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2013
Brandon C Polander Bridgette A Barry

In photosynthesis, photosystem II evolves oxygen from water by the accumulation of photooxidizing equivalents at the oxygen-evolving complex (OEC). The OEC is a Mn4CaO5 cluster, and its sequentially oxidized states are termed the Sn states. The dark-stable state is S1, and oxygen is released during the transition from S3 to S0. In this study, a laser flash induces the S1 to S2 transition, which...

2017
Justin A. Schulte

In this paper, it is proposed that coastal flood ensemble forecasts be partitioned into sub-ensemble forecasts using cluster analysis in order to produce representative statistics and to measure forecast uncertainty arising from the presence of clusters. After clustering the ensemble members, the ability to predict the cluster into which the observation will fall can be measured using a cluster...

Journal: :Physical chemistry chemical physics : PCCP 2013
Eric S Shamay Nicholas A Valley Frederick G Moore Geraldine L Richmond

A water surface is a dynamic and constantly evolving terrain producing a vast array of unique molecular properties and interactions with chemical species in the environment. The complex dynamics of water surfaces permit life on earth to continue, but also complicate the development of a complete microscopic picture of the specific behaviors that take place within interfacial aqueous environment...

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