The Second Hydration Shell of Li+ in Aqueous LiI from X-Ray and MD Studies

1981 ◽  
Vol 36 (10) ◽  
pp. 1076-1082 ◽  
Author(s):  
T. Radnai ◽  
G. Pálinkás ◽  
Gy I. Szász ◽  
K. Heinzinger
Keyword(s):  
Hydration Shell ◽  
Distribution Functions ◽  
Dynamics Simulation ◽  
Scattering Data ◽  
Water Molecules ◽  
Radial Distribution Functions ◽  
Partial Structure ◽  
X Ray ◽  
Total Structure ◽  
First Hydration Shell

Indications from a molecular dynamics simulation of a 2.2 molal LiI solution of the existence of a second hydration shell of Li+ have been checked by an x-ray investigation of the same solution. The scattering data are analysed via partial structure functions and radial distribution functions which have been obtained from a model fitted to the total structure function. Experiment and simulation agree on first neighbor ion-water distances. An octahedral arrangement of six water molecules in the first hydration shell of Li+ and additional twelve water molecules in the second shell have been verified by the experiment.

A Molecular Dynamics Study of the Structure of an Aqueous CsF Solution

1983 ◽  
Vol 38 (2) ◽  
pp. 214-224 ◽  
Author(s):  
Gy. I. Szász ◽  
K. Heinzinger
Keyword(s):  
Molecular Dynamics ◽  
Hydration Shell ◽  
Distribution Functions ◽  
Dynamics Simulation ◽  
Water Model ◽  
Water Molecules ◽  
Heat Of Solution ◽  
Average Temperature ◽  
Experimental Density ◽  
First Hydration Shell

Abstract A molecular dynamics simulation of a 2.2 molal aqueous CsF solution has been performed employing the ST2 water model. The basic periodic cube with a sidelength of 18.50 Å contained 200 water molecules, and 8 ions of each kind, corresponding to an experimental density of 1.26 g/cm3. The simulation extended over 6.5 ps with an average temperature of 307 K. The structure of the solution is discussed by means of radial distribution functions and the orientation of the water molecules. The computed hydration numbers in the first shell of Cs+ and F- are 7.9 and 6.8, respectively; the corresponding first hydration shell radii are 3.22 A and 2.64 A, respectively. Values for the hydration shell energies and the heat of solution have been calculated.

Spin-state dependence of the structural and vibrational properties of solvated iron(ii) polypyridyl complexes from AIMD simulations: II. aqueous [Fe(tpy)2]Cl2

2019 ◽  
Vol 21 (2) ◽  
pp. 650-661 ◽  
Author(s):  
Latévi M. Lawson Daku
Keyword(s):  
Hydration Shell ◽  
State Dependence ◽  
Distribution Functions ◽  
Water Molecules ◽  
Radial Distribution Functions ◽  
Spin States ◽  
Polypyridyl Complexes ◽  
Coordination Numbers ◽  
A Chain ◽  
First Hydration Shell

LS and HS Fe–O radial distribution functions and running coordination numbers for aqueous [Fe(tpy)2]Cl2: in both spin states, the first hydration shell of [Fe(tpy)2]2+ consists in a chain of ∼15 hydrogen-bonded water molecules wrapped around the ligands.

Hydration Shell Structures in an MgCl2 Solution from X-Ray and MD Studies

1982 ◽  
Vol 37 (9) ◽  
pp. 1049-1060 ◽  
Author(s):  
G. Pálinkás ◽  
T. Radnai
Keyword(s):  
Nearest Neighbor ◽  
Hydration Shell ◽  
Lone Pair ◽  
Model Fit ◽  
Dynamics Simulation ◽  
Scattering Data ◽  
Water Molecules ◽  
X Ray ◽  
Hydration Shells ◽  
Density Maps

Abstract The results of a molecular dynamics simulation of a 1.1 molal aqueous MgCl2 solution are com-pared with newly performed x-ray measurements. The structural properties of the solution are evaluated from the scattering data by a model fit to the experimental structure function. The comparison on the basis of fit parameters and partial structure functions shows an overall good agreement between experiment and simulation.Detailed information on the structure of the hydration shells is deduced from the simulation and shown in form of density maps and angular distributions. It is demonstrated that the octahedral arrangement of the water molecules in the first hydration shell of Mg++ is strongly pronounced while it is only indicated in the case of Cl-. A preferential arrangement in tetrahedral directions has been found for the nearest neighbor water molecules around a central water molecule with an asymmetry in respect to lone pair and hydrogen atom directions. In addition, the probability of finding water molecules at a given number of symmetry sites at the same time has been calculated.

Molecular Dynamics and X-Ray Diffraction Study of Aqueous Beryllium(II) Chloride Solutions

1986 ◽  
Vol 41 (10) ◽  
pp. 1175-1185 ◽  
Author(s):  
T. Yamaguchi ◽  
H. Ohtaki ◽  
E. Spohr ◽  
G. Pálinkás ◽  
K. Heinzinger ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Md Simulation ◽  
Hydration Shell ◽  
Dynamics Simulation ◽  
Scattering Data ◽  
Water Molecules ◽  
Force Model ◽  
X Ray Diffraction ◽  
X Ray ◽  
Three Body

A structural investigation of a 1.1 molal BeCl2 aqueous solution has been performed by a molecular dynamics simulation together with X-ray diffraction studies of 1.1 and 5.3 molal BeCl2 aqueous solutions at pH =1. A central force model in combination with an improved intramolecular three-body potential was used for water. The ion-water and ion-ion potentials were derived from ab initio calculations. The structure function obtained from the simulation is in satisfactory agreement with that from X-ray diffraction. The MD simulation of the 1.1 molal solution shows that the hydration shell o f Be2+ consists of six water molecules occupying octahedral sites around a central Be2+. The X-ray scattering data of the 5.3 molal solution indicate that Be2+ has only four water molecules in the first hydration shell. The average coordination number of Cl- is found to be about seven in the 1.1 molal solution from both X-ray diffraction and MD simulation, but Cl- is surrounded on the average by 3.4 water molecules in the 5.3 molal solution. The influence of the small divalent Be2+ on the geometry of its nearest neighbour water molecules is compared with the results of previous simulations of 1.1 molal MgCl2 and CaCl2 solutions.

Molecular Dynamics Simulation of an Aqueous MgCl2 Solution. Structural Results

1982 ◽  
Vol 37 (9) ◽  
pp. 1038-1048 ◽  
Author(s):  
W. Dietz ◽  
W. O. Riede ◽  
K. Heinzinger
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Hydration Shell ◽  
Distribution Functions ◽  
Dynamics Simulation ◽  
Water Molecules ◽  
Force Model ◽  
Average Temperature ◽  
Pair Potentials ◽  
Effective Pair

Abstract A molecular dynamics simulation of a 1.1 molal aqueous MgCl2 solution has been performed employing the central force model for water. The effective pair potentials for ion-water have been derived from ab initio calculations. The basic box with a sidelength of 18.30 Å contained 200 water molecules, 8 anions and 4 cations, corresponding to an experimental density of 1.079 g/cm3 . The simulation extended over about 3.3 picoseconds at an average temperature of 309 K. The structure of the solution is described by radial distribution functions and the orientation of the water molecules in respect to physically meaningful directions. Values for the dielectric constant and hydration energies have been calculated. The strong influences of the twofold charged magnesium ion on the geometry of the water molecules and the structure of the hydration shell is discussed in comparison with the results of a previous simulation of a 2.2 molal NaCl solution.

X-Ray Diffraction Study on Hydration and Ion-Pairing in Aqueous ZnSO4 Solution

1982 ◽  
Vol 37 (11) ◽  
pp. 1247-1252 ◽  
Author(s):  
T. Radnai ◽  
G. Pálinkás ◽  
R. Caminiti
Keyword(s):  
Aqueous Solution ◽  
Hydration Shell ◽  
Sulfate Group ◽  
Water Molecules ◽  
Diffraction Experiment ◽  
X Ray Diffraction ◽  
X Ray ◽  
Experimental Structure ◽  
Molecular Description ◽  
First Hydration Shell

An X-ray diffraction experiment on a 2.98 molar ZnSO4 aqueous solution has been interpreted in terms of coordination models. The best agreement between model and experimental structure functions was reached when the Zn2+ ion is hydrated in octahedral form, with twelve water molecules in a second hydration shell, bonded by shortened H-bonds to the first hydration shell. The sulfate group is loosely coordinated by 8.2 water molecules. Besides the dominating Zn(H2O)2+6 complexes, about 40% [Zn(H2O)5SO4] inner complexes were found to be consistent with the X-ray data. Alternative models of cationic hydration are critically examined and for the sulfate group the independent atom approximation is compared with a spherical molecular description.

scholarly journals Structure of aqueous sodium acetate solutions by X-Ray scattering and density functional theory

2020 ◽  
Vol 92 (10) ◽  
pp. 1627-1641
Author(s):  
Guangguo Wang ◽  
Yongquan Zhou ◽  
He Lin ◽  
Zhuanfang Jing ◽  
Hongyan Liu ◽  
...  
Keyword(s):  
Sodium Acetate ◽  
Density Functional ◽  
Hydration Shell ◽  
Ion Pair ◽  
Water Molecules ◽  
Sodium Acetate Solution ◽  
Acetate Solution ◽  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering

AbstractThe structure of aq. sodium acetate solution (CH3COONa, NaOAc) was studied by X-ray scattering and density function theory (DFT). For the first hydrated layer of Na+, coordination number (CN) between Na+ and O(W, I) decreases from 5.02 ± 0.85 at 0.976 mol/L to 3.62 ± 1.21 at 4.453 mol/L. The hydration of carbonyl oxygen (OC) and hydroxyl oxygen (OOC) of CH3COO− were investigated separately and the OC shows a stronger hydration bonds comparing with OOC. With concentrations increasing, the hydration shell structures of CH3COO− are not affected by the presence of large number of ions, each CH3COO− group binds about 6.23 ± 2.01 to 7.35 ± 1.73 water molecules, which indicates a relatively strong interaction between CH3COO− and water molecules. The larger uncertainty of the CN of Na+ and OC(OOC) reflects the relative looseness of Na-OC and Na-OOC ion pairs in aq. NaOAc solutions, even at the highest concentration (4.453 mol/L), suggesting the lack of contact ion pair (CIP) formation. In aq. NaOAc solutions, the so called “structure breaking” property of Na+ and CH3COO− become effective only for the second hydration sphere of bulk water. The DFT calculations of CH3COONa (H2O)n=5–7 clusters suggest that the solvent-shared ion pair (SIP) structures appear at n = 6 and become dominant at n = 7, which is well consistent with the result from X-ray scattering.

Structural Study of a Decagonal Al75Fe15Ni10 Alloy by Anomalous X-ray Scattering (AXS) Method

1991 ◽  
Vol 46 (7) ◽  
pp. 605-608 ◽  
Author(s):  
E. Matsubara ◽  
Y. Waseda ◽  
A. P. Tsai ◽  
A. Inoue ◽  
T. Masumoto
Keyword(s):  
Structural Study ◽  
Radial Distribution ◽  
Distribution Functions ◽  
Radial Distribution Functions ◽  
X Ray Diffraction ◽  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering

A structural study of an as-quenched decagonal Al75Fe15Ni10 alloy has been carried out by anomalous x-ray scattering (AXS) as well as ordinary x-ray diffraction. The environmental radial distribution functions (RDFs) for Fe and Ni determined by the AXS measurements turned out to resemble each other and to be similar to the ordinary RDF obtained by ordinary x-ray diffraction. These results clearly show that the Ni and Fe atoms are homogeneously distributed and occupy the same sites in the decagonal structure of Al75Fe15Ni10.

Extracting differential pair distribution functions usingMIXSCAT

2010 ◽  
Vol 43 (3) ◽  
pp. 635-638 ◽  
Author(s):  
Caroline Wurden ◽  
Katharine Page ◽  
Anna Llobet ◽  
Claire E. White ◽  
Thomas Proffen
Keyword(s):  
Distribution Functions ◽  
Program Package ◽  
Scattering Data ◽  
X Ray ◽  
Differential Structure ◽  
Structure Factors ◽  
Differential Pair ◽  
User Friendly ◽  
Pair Distribution Functions

Differently weighted experimental scattering data have been used to extract partial or differential structure factors or pair distribution functions in studying many materials. However, this is not done routinely partly because of the lack of user-friendly software. This paper presentsMIXSCAT, a new member of theDISCUSprogram package.MIXSCATallows one to combine neutron and X-ray pair distribution functions and extract their respective differential functions.

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