Dimerization Behavior of Methyl Chlorophyllide a as the Model of Chlorophyll a in the Presence of Water Molecules—Theoretical Study

2019 ◽  
Vol 59 (5) ◽  
pp. 2123-2140 ◽  
Author(s):  
Michał Chojecki ◽  
Dorota Rutkowska-Zbik ◽  
Tatiana Korona
Keyword(s):  
Chlorophyll A ◽  
Theoretical Study ◽  
Water Molecules

Defects controlled by acid-modulators and water molecules enabled UiO-67 for exceptional toluene uptakes: An experimental and theoretical study

2021 ◽  
pp. 131573
Author(s):  
Xiaodong Zhang ◽  
Xiaoyu Shi ◽  
Qiangyu Zhao ◽  
Yintao Li ◽  
Jinfeng Wang ◽  
...  
Keyword(s):  
Theoretical Study ◽  
Water Molecules

Theoretical study of the magnetic properties of water molecules in non-uniform magnetic fields

1994 ◽  
Vol 305 ◽  
pp. 89-99 ◽  
Author(s):  
M.C. Caputo ◽  
M.B. Ferraro ◽  
P. Lazzeretti ◽  
M. Malagoli ◽  
R. Zanasi
Keyword(s):  
Magnetic Properties ◽  
Magnetic Fields ◽  
Theoretical Study ◽  
Water Molecules

Dissociation of H2O molecule adsorbed on Si (001) 2×1 surface: a theoretical study

2008 ◽  
Vol 1145 ◽  
Author(s):  
Hyun-Chul Oh ◽  
Hwa-Il Seo ◽  
Yeong-Cheol Kim
Keyword(s):  
Water Molecule ◽  
Room Temperature ◽  
Surface Coverage ◽  
Theoretical Study ◽  
Surface Model ◽  
Water Molecules ◽  
First Principles Calculations ◽  
Adsorption Sites ◽  
Adsorption Surface ◽  
Adsorption And Dissociation

AbstractThe adsorption and dissociation behavior of water molecule below and above the critical dissociation temperatures were studied by first principles calculations. We found that water-molecule adsorption (surface coverage, θ=0.25) on the down Si atom of a Si dimer in two dimers surface model was 0.26 eV more favorable than that on the up Si atom. The activation energies of water molecule on the down Si atom for interdimer and intradimer dissociations were 0.17 eV and 0.20 eV, respectively. Due to the lower activation energy, the water molecule splits into H and OH immediately once it adsorbs on down Si atom of the Si (001) surface at room temperature. There were three different adsorption sites among four sites of the two dimers for the second water molecule (θ=0.5): one was preoccupied by OH of the first water molecule; up Si atom of the same-dimer with 76.3 % probability, up Si atom of the adjacent-dimer with 23.6 % probability, and down Si atom of the adjacent-dimer with 0.1 % probability. Thus, ½ monolayer of OH sites on the Si (001) surface are irregularly distributed when water molecules are adsorbed and dissociated at room temperature.

Ligand-exchange mechanism: new insight into solid-phase extraction of uranium based on a combined experimental and theoretical study

2015 ◽  
Vol 17 (11) ◽  
pp. 7214-7223 ◽  
Author(s):  
Yin Tian ◽  
Jia Fu ◽  
Yi Zhang ◽  
Kecheng Cao ◽  
Chiyao Bai ◽  
...  
Keyword(s):  
Solid Phase Extraction ◽  
Ligand Exchange ◽  
Theoretical Study ◽  
Solid Phase ◽  
Exchange Process ◽  
Water Molecules ◽  
Phase Extraction ◽  
Extraction Mechanism ◽  
Coordinated Water ◽  
Insight Into

The extraction mechanism is an exchange process between the ligands on Urea-GO and the coordinated water molecules of uranyl.

scholarly journals Theoretical Study of the Microhydration of 1-Chloro and 2-Chloro Ethanol as a Clue for Their Relative Propensity Toward Dehalogenation

2018 ◽  
Author(s):  
George Petsis ◽  
Zoi Salta ◽  
Agnie M. Kosmas ◽  
Oscar Ventura
Keyword(s):  
Density Functional ◽  
Theoretical Study ◽  
Initial Step ◽  
Water Molecules ◽  
Water Solvent ◽  
Functional Methods ◽  
Electronic Distribution ◽  
Standard Reaction ◽  
Hydrogen Bonded

<p>This work reports a computational analysis of hydrogen bonded clusters of mono-, di-, tri- and tetra hydrates of the chlorohydrins CH<sub>3</sub>CHClOH (1ClEtOH) and CH<sub>2</sub>ClCH<sub>2</sub>OH (2ClEtOH). The goal of the study is to assess the role of the water solvent into the facilitation of the initial step for dehalogenation of these compounds, a process of interest in several contexts. Molecular orbital methods (MP2), density functional methods (B3LYP, M06 and wB97X-D) and composite model chemistries (CBS-QB3, G4) were employed to investigate the structure, electronic distribution and hydrogen-bonded structure of 7 monohydrates, 6 dihydrates, 5 trihydrates and 5 tetrahydrates of both species. Standard reaction enthalpy and standard Gibbs free reaction energy were computed for all aggregates with respect to <b><i>n</i></b> independent water molecules and with respect to the dimer, trimer and tetramer of water, respectively, in order to evaluate stability and hydrogen bonding network. The influence of the water chains on the length and vibrational frequencies, especially of the C-Cl and O-H bonds, was evaluated.</p>

Sign in / Sign up

Export Citation Format

Share Document