Theoretical approaches to the intermolecular nature of water

doi:10.1098/rstb.1977.0033

Cited by 29 publications

(7 citation statements)

References 40 publications

(32 reference statements)

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“…The lower the temperature, the stronger this distortional effect of the applied pressure seems to be. This is consistent with the view that strong supercooling leads to an increased straightening of 0 -H ..O-bonds in the random hydrogen bonded network and that the major effect of pressure in the low pressure region is to deform hydrogen bond angles [42,43]. This tendency is not found at higher pressures.…”

Section: ) Estimate Of the Deuterium Quadrupole Coupling Constant ( supporting

confidence: 90%

Pressure and Temperature Dependence of the Longitudinal Deuterium Relaxation Times in Supercooled Heavy Water to 300 MPa and 188 K

Lang

Lüdemann

1980

Ber Bunsenges Phys Chem

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The longitudinal deuteron relaxation times T1 in heavy water have been determined at 15.4 MHz in the temperature range from T = 283 K to 188 K and up to pressures of 300 MPa. Between 283 K and 200 K all isotherms exhibit pronounced maxima of T1 in the pressure range between 150 MPa and 300 MPa. This maximum is most pronounced in the 242 K isotherm, where T1 increases more than fourfold from 17 ms at 0.1 MPa to 73 ms at 250 MPa. The 225 MPa isobar runs at 192 K through a minimum: T1 = 0.5 ms. Under the assumption of isotropic reorientation one derives from the minimum condition (ω0 ·τθ ⋍ 0.62) the deuteron quadrupole coupling constant for D2O to CDQC = 214 ± 12 kHz. The isobaric temperature dependence of the correlation times τθ can be described at p ≥ 200 MPa by the VTF‐equation. At p ≤ 100 MPa τθ increases faster with falling temperature than predicted by the VTF‐equation. In this range the isobars are best represented by an equation proposed by Speedy and Angell: The determination of τθ permits an estimate of the viscosity η and the self‐diffusion coefficient D for D2O in the supercooled range. Around T = 190 K and p = 225 MPa one gets η ⋍ 4 Pa · s and D ⋍ 6 · 10−9 cm2/s.

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Section: ) Estimate Of the Deuterium Quadrupole Coupling Constant ( supporting

confidence: 90%

Pressure and Temperature Dependence of the Longitudinal Deuterium Relaxation Times in Supercooled Heavy Water to 300 MPa and 188 K

Lang

Lüdemann

1980

Ber Bunsenges Phys Chem

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“…There are several approaches that estimate the lifetime directly from this probability function (i.e., the “intermittent” approach , ). In contrast, the reactive flux method eliminates perturbations from diffusion with the aid of a second state in which the pair of interest is not connected by a hydrogen bond but is still within a distance that a hydrogen bond could be reformed.…”

Section: Reactive Flux Approachmentioning

confidence: 99%

Robustness of the Hydrogen Bond and Ion Pair Dynamics in Ionic Liquids to Different Parameters from the Reactive Flux Method

Gehrke

Kirchner

2019

J. Chem. Eng. Data

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Both hydrogen bonding and ionic interactions have an extreme influence on the properties of all kinds of materials. Ionic liquids mostly possess both of them. In the present work, we calculate with the aid of the reactive flux theory the dynamics of hydrogen bonds as well as of the ionic network for different 1-butyl-3-methylimidazolium-based ionic liquids. To apply this method, we carry out molecular dynamics simulations over broad temperature and simulation parameter ranges. Hydrogen bond lifetimes vary with temperature in the range of 10 ps (400 K)−60 ps (300 K) for the more fluid systems to 60 ps (400 K)−2000 ps (300 K) for the more viscous systems. The ion pair dynamics behave differently. While the more fluid systems show ion pairs which possess a factor of 4 longer lifetimes than the hydrogen bonds, the ion pair lifetimes of the more viscous systems actually are a factor of 0.6 smaller and thus faster than the hydrogen bond lifetimes. Although the choice of the hydrogen bond angle is less sensitive, a deviation in the distance criterion of up to 5% from the radial pair distribution functions' minimum leads to a change of less than 10% in the calculated lifetime. The ion pair dynamics are less sensitive with respect to the variation of the geometrical parameter. Interestingly, for both kinds of dynamics the impact on the activation energy is even less prone to the different cutoff values than the lifetime. In fact, the cutoff for the distance criteria causes the activation energies to remain almost unchanged. We find that the stability of the method is sufficient if the simulation time is at least a factor of 10 longer than the corresponding lifetime.

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“…(1) All-atom models and convergence problems The pioneering simulation of the properties of liquid water by Barker & Watts (1969) and by Stillinger & Rahman (Rahman & Stillinger, 1971;Stillinger & Rahman, 1974;Stillinger, 1977) and subsequent studies (Watts, 1974;McDonald & Klein, 1978;Owicki & Scheraga, 1977;van Gunsteren, Berendsen & Rullman, 1978;Barnes et al 1979;Berendsen et al 1981;Jorgensen, 1981Jorgensen, , 1982Mezei & Beveridge, 1982;Berens etal. 1983;White & Wilson, 1984) have demonstrated that pure polar solvents can be simulated in a computationally manageable way.…”

Section: (B) Simulating Electrostatic Energies In Polar Solventsmentioning

confidence: 99%

Calculations of electrostatic interactions in biological systems and in solutions

Warshel

Russell

1984

Quart. Rev. Biophys.

1,010

915

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Correlating the structure and action of biological molecules requires knowledge of the corresponding relation between structure and energy. Probably the most important factors in such a structure– energy correlation are associated with electrostatic interactions. Thus the key requirement for quantative understanding of the action of biological molecules is the ability to correlate electrostatic interactions with structural information. To appreciate this point it is useful to compare the electrostatic energy of a charged amino acid in a polar solvent to the corresponding van der Waals energy. The electrostatic free energy, ΔGel, can be approximated (as will be shown in Section II) by the Born formula (ΔGel = –(166Q2/ā) (I – I/E)). Where ΔGel is given in kcal/mol, Qis the charge of the given group, in units of electron charge, āis the effective radius of the group, and E is the dielectric constant of the solvent. With an effective radius of charged amino acids of approximately 2 Å, Born's formula gives about – 80 kcal/mol for their energy in polar solvents where E is larger than 10. This energy is two orders of magnitude larger than the van der Waals interaction of such groups and their surroundings.

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Theoretical approaches to the intermolecular nature of water

Cited by 29 publications

References 40 publications

Pressure and Temperature Dependence of the Longitudinal Deuterium Relaxation Times in Supercooled Heavy Water to 300 MPa and 188 K

Pressure and Temperature Dependence of the Longitudinal Deuterium Relaxation Times in Supercooled Heavy Water to 300 MPa and 188 K

Robustness of the Hydrogen Bond and Ion Pair Dynamics in Ionic Liquids to Different Parameters from the Reactive Flux Method

Calculations of electrostatic interactions in biological systems and in solutions

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