Activation Energies of the Proton‐exchange Reactions in Water Measured with the <sup>1</sup>H‐NMR Spin Echo Technique

Pfeifer, Rene; Hertz, H. G.

doi:10.1002/bbpc.199000030

Cited by 38 publications

(23 citation statements)

References 22 publications

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“…More than 20 years ago [53], we investigated the (still) unresolved problem of excess mobility of hydrogen (and hydroxyl) ions in aqueous solutions with K + and Na + ions (and Cl -for the hydroxyl ion) as background. The model, based on coherent dissipative dynamics, more or less identical to the concepts above, led to predictions that actually confirmed and predicted contemporary NMR spin-echo experiments [70,71].…”

Section: Consciousness As An Irreducible Processsupporting

confidence: 58%

The Origin and Evolution of Complex Enough Systems in Biology

Brändas

2017

Quantum Systems in Physics, Chemistry, and Biology

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Recent criticisms of Neo-Darwinism are considered and disputed within the setting of recent advances in chemical physics. A related query, viz., the ontological thesis, that everything is physical, confronts a crucial test on the validity of reductionism as a fundamental approach to science. While traditional 'physicalism' interprets evolution as a sequence of physical accidents governed by the second law of thermodynamics, the concepts of biology concern processes that owe their goal-directedness to the influence of an evolved program. This disagreement is met by unifying basic aspects of chemistry and physics, formulating the Correlated Dissipative Ensemble, CDE, as a characterization of a 'complex enough systems', CES, in biology. The latter entreats dissipative dynamics; non-Hermitian quantum mechanics together with modern quantum statistics thereby establish a precise spatio-temporal order of significance for living systems. The CDE grants a unitary transformation structure that comprises communication protocols of embedded Poisson statistics for molecular recognition and cellular differentiation, providing cell-hierarchies in the organism. The present conception of evolution, founded on communication with a built-in self-referential order, offers a valid argument in favour of Neo-Darwinism, providing an altogether solid response and answer to the criticisms voiced above. Introductory Remarks Reductionism in Natural ScienceA frequent understanding of natural sciences contends that biology reduces to chemistry and chemistry to physics. Even if the traditional analytic interpretation of mathematics as a language or tool to convert knowledge about nature, i.e. a formal science not being incorporated amongst the branches of physical or life sciences, some recent propositions impart that also physics can be reduced to mathematics [1]. Within such views, based on strict reductionnism, see more below, one argues that the present laws of physics are not only commensurate to biology, but also contain the necessary natural laws for expressing all the known biological facts.There are numerous differences of opinion regarding the scheme outlined above, e.g. the impossibility to derive the Coulomb Hamiltonian corresponding to a molecule from first principles and the general problem of quantum chemistry to treat nuclei and electrons on a more or less equivalent basis, see Löwdin [2]. Other arguments concern the concepts of biology as the laws of physics, at present, exclude a fundamental understanding of biological processes governed by an evolved program [3,4].Observation and deliberate experiments instigate rational, deductive theory, formulated in the language of mathematics, with the so accumulated knowledge discussed and contained by the methods of philosophy in general and the concepts of biology in particular. Recognizing the acquired demarcation between the philosophy of science, including biology, and the enactment of reductionism as embodied in the laws of physics, the endwise connections between them ...

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Section: Consciousness As An Irreducible Processsupporting

confidence: 58%

The Origin and Evolution of Complex Enough Systems in Biology

Brändas

2017

Quantum Systems in Physics, Chemistry, and Biology

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“…A few PT can be still seen at 150 K and even one of them has been captured at 100 K (given the short time interval considered here). We should point out that the predicted rate of transfer at ambient conditions is a factor ∼8 larger than the one inferred from results of NMR experiments [56][57][58], being that this a well-known deficiency of the semi-classical picture adopted here; moreover, the explicit incorporation of quantum fluctuations in the transferring proton yields a better agreement with the experiments, leading to rates at least twice as large as the semi-classical ones [43].…”

Section: B Dynamics Of Proton Transfermentioning

confidence: 51%

Dynamical aspects of intermolecular proton transfer in liquid water and low-density amorphous ices

Tahat

Martı́

2014

Phys. Rev. E

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The microscopic dynamics of an excess proton in water and in low-density amorphous ices has been studied by means of a series of molecular dynamics simulations. Interaction of water with the proton species was modelled using a multistate empirical valence bond Hamiltonian model. The analysis of the effects of low temperatures on proton diffusion and transfer rates has been considered for a temperature range between 100 and 298 K at the constant density of 1 g cm −3 . We observed a marked slowdown of proton transfer rates at low temperatures, but some episodes are still seen at 100 K. In a similar fashion, mobility of the lone proton gets significantly reduced when temperature decreases below 273 K. The proton transfer in low-density amorphous ice is an activated process with energy barriers between 1-10 kJ/mol depending of the temperature range considered and eventually showing Arrhenius-like behavior. Spectroscopic data indicated the survival of both Zundel and Eigen structures along the whole temperature range, revealed by significant spectral frequency shifts.

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“…Using a random walk description, the abnormal proton in water mobility is characterized with a hopping time, τ p , of ∼1.5 ps at room temperature, as deduced from NMR line-narrowing investigations. [32][33][34] This time scale reproduces the abnormal proton mobility with a hopping length, l p , of 2.5-2.6 Å, which is the O-O distance in H 9 O 4 + . 35 Bernal and Fowler 36 proposed that the rate-determining step of prototropic mobility in liquid water is connected to single water rotation.…”

Section: Introductionmentioning

confidence: 77%

Temperature Dependence of Proton Diffusion in I_h Ice

et al. 2009

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The temperature dependence of the proton diffusion constant, D H + , in methanol-doped ice was studied over the wide temperature range of 80-260 K. For that purpose, we measured the time-resolved fluorescence of a flavin mononucleotide (FMN) and riboflavin in ice doped with HCl or HF. The analysis of the fluorescence quenching provided the value of D H + . We found that the temperature dependence of D H + at T > 235 K is rather small, whereas at T < 235 K, it is rather large. These temperature-dependence results are similar to previous conductivity measurements. We used a stepwise, two-coordinate qualitative proton transfer model to explain the temperature dependence of D H + in ice.

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Activation Energies of the Proton‐exchange Reactions in Water Measured with the ¹H‐NMR Spin Echo Technique

Cited by 38 publications

References 22 publications

The Origin and Evolution of Complex Enough Systems in Biology

The Origin and Evolution of Complex Enough Systems in Biology

Dynamical aspects of intermolecular proton transfer in liquid water and low-density amorphous ices

Temperature Dependence of Proton Diffusion in I_h Ice

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Activation Energies of the Proton‐exchange Reactions in Water Measured with the 1H‐NMR Spin Echo Technique

Cited by 38 publications

References 22 publications

The Origin and Evolution of Complex Enough Systems in Biology

The Origin and Evolution of Complex Enough Systems in Biology

Dynamical aspects of intermolecular proton transfer in liquid water and low-density amorphous ices

Temperature Dependence of Proton Diffusion in Ih Ice

Contact Info

Product

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Activation Energies of the Proton‐exchange Reactions in Water Measured with the ¹H‐NMR Spin Echo Technique

Temperature Dependence of Proton Diffusion in I_h Ice