scholarly journals The Interaction Energy of an Isolated Monovalent Ion

1968 ◽  
Vol 21 (5) ◽  
pp. 597 ◽  
Author(s):  
DK Ross
Keyword(s):  
Dipole Moment ◽  
Aqueous Medium ◽  
Interaction Energy ◽  
Dipole Moments ◽  
Hydration Shell ◽  
Water Molecules ◽  
Li Ion ◽  
Monovalent Ion ◽  
First Hydration Shell

The interaction energy of a monovalent ion in an aqueous medium at 25�C is determined. It is also found that the water molecules in the first hydration shell of the ion have a mean dipole moment far in excess of their permanent dipole moments. Thus, for example, the increase in the dipole moment of the attached water molecules. due to the presence of an ion is about 60% for the small four-coordinated Li+ ion and about 30% for the larger four-coordinated 1- ion. Calculations are also carried out on the assumption that the ions are six coordinated.

The dipole moment of water in the first hydration shell of a monovalent ion

1968 ◽  
Vol 46 (21) ◽  
pp. 2407-2411 ◽  
Author(s):  
Dieter K. Ross
Keyword(s):  
Dielectric Constant ◽  
Dipole Moment ◽  
Continuous Medium ◽  
Hydration Shell ◽  
Bulk Water ◽  
Water Molecules ◽  
The Mean ◽  
Monovalent Ion ◽  
Coordinated Water ◽  
First Hydration Shell

The mean dipole moment of the water molecules in contact with a monovalent ion is estimated. The first hydration shell of a spherical ion is assumed to contain either four or six coordinated water molecules, while the water molecules outside this shell are replaced by a continuous medium whose dielectric constant is that corresponding to bulk water at 25 °C. It is found that the dipole moment induced in the attached water molecules is comparable with its permanent dipole moment.

scholarly journals Positively and Negatively Hydrated Counterions in Molecular Dynamics Simulations of DNA Double Helix

2020 ◽  
Vol 65 (6) ◽  
pp. 510
Author(s):  
S. Perepelytsya
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Double Helix ◽  
Dipole Moments ◽  
Hydration Shell ◽  
Minor Groove ◽  
Water Molecules ◽  
Negative Hydration ◽  
Dynamics Simulations ◽  
Dna Double Helix

The DNA double helix is a polyanionic macromolecule that is neutralized in water solutions by metal ions (counterions). The property of counterions to stabilize the water network (positive hydration) or to make it friable (negative hydration) is important in terms of the physical mechanisms of stabilization of the DNA double helix. In the present research, the effects of positive hydration of Na+ counterions and negative hydration of K+ and Cs+ counterions incorporated into the hydration shell of the DNA double helix have been studied using molecular dynamics simulations. The results have shown that the dynamics of the hydration shell of counterions depends on the region of the double helix: minor groove, major groove, and outside the macromolecule. The longest average residence time has been observed for water molecules contacting with the counterions localized in the minor groove of the double helix (about 50 ps for Na+ and lower than 10 ps for K+ and Cs+). The estimated potentials of the mean force for the hydration shells of counterions show that the water molecules are constrained too strongly, and the effect of negative hydration for K+ and Cs+ counterions has not been observed in the simulations. The analysis has shown that the effects of counterion hydration can be described more accurately with water models having lower dipole moments.

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.

Dielectric dispersion and dipole moment of myoglobin in water

1972 ◽  
Vol 328 (1574) ◽  
pp. 371-387 ◽  
Keyword(s):  
Crystal Structure ◽  
Dipole Moment ◽  
Protein Concentration ◽  
Hydration Shell ◽  
Sperm Whale ◽  
Dielectric Dispersion ◽  
Water Molecules ◽  
Solution Conductivity ◽  
Sperm Whale Myoglobin ◽  
Good Agreement

The parameters of dielectric dispersion at radio frequencies in aqueous solutions of horse and sperm whale myoglobin have been measured as functions of protein concentration, solution conductivity and temperature. From these dependences it is shown that, of the likely interpretations, the mechanism of molecular rotation is best able to account for the observed dispersion. The results are consistent with a dipole moment of around 150D for the myoglobin molecule and a hydration shell of about two water molecules thickness. This value of dipole moment is shown to be in good agreement with that obtained from calculations based on the known crystal structure.

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.

scholarly journals On the microscopic origin of the cryoprotective effect in lysine solutions

2020 ◽  
Vol 22 (13) ◽  
pp. 6919-6927 ◽  
Author(s):  
Andrés Henao ◽  
Guadalupe N. Ruiz ◽  
Nicola Steinke ◽  
Silvina Cerveny ◽  
Roberto Macovez ◽  
...  
Keyword(s):  
Amino Acid ◽  
Hydration Shell ◽  
Water Molecules ◽  
Microscopic Origin ◽  
First Hydration Shell

Lysine cryoprotective properties are due to the tight bonding of the first hydration Shell to the amino acid. However this effect is only possible for concentration up to 5.4 water molecules per lysine.

Sign in / Sign up

Export Citation Format

Share Document