Salty Water in KOH-Doped Hexagonal Ice: a Proton and Deuteron NMR Study

Schildmann, S.; Scholer, A.-C.; Nowaczyk, A.; Geil, Burkhard; Böhmer, Roland

doi:10.1007/s00723-012-0414-x

Cited by 4 publications

(4 citation statements)

References 44 publications

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“…49 At a microscopic level, ion concentration can also play a critical role in ice transport properties as it can lead to localized phase change behavior. Both our experimental measurement of the conductivity and other studies using techniques such as nuclear magnetic resonance 50 suggested that the liquid-like phase often coexists with the ice crystal when the concentration of KOH is more than 10 mM. Further studies of hydroxide diffusive behavior in the ice at different concentrations will be conducted in our future works to provide a more comprehensive explanation of the experimental data.…”

Section: Introductionmentioning

confidence: 57%

Machine Learning Analysis of the Thermodynamic Responses of In Situ Dielectric Spectroscopy Data in Amino Acids and Inorganic Electrolytes

et al. 2020

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Dielectric spectroscopy (DS) can be a robust in situ technique for geochemical applications. In this study, we applied deeplearning techniques to DS measurement data to enable rapid science interrogation and identification of electrolyte solutions containing salts and amino acids over a wide temperature range (20 to −60 °C). For the purpose of searching for signs of life, detecting amino acids is a fundamental high priority for field and planetary instruments as amino acids are one of the building blocks for life as we know it. A convolutional neural network (CNN) with channel-wise one-dimensional filters is proposed to fulfill the task, using the DS data of amino acid and inorganic salt solutions. Experimental results show that the CNN with two convolutional layers and one fully connected layer can effectively differentiate solutions containing amino acids from those containing salts in both the liquid and solid (water ice) states. To complement the experimental measurements and CNN analysis, the diffusive behaviors of ions (K + , Cl − , and OH − ) were further discussed with atomistic molecular dynamics simulations performed in this work as well as the quantum simulation published in the literature. Combining DS with machine-learning techniques and simulations will greatly facilitate more real-time decision-making of mobility systems for future exploratory endeavors in other worlds beyond Earth.

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Section: Introductionmentioning

confidence: 57%

Machine Learning Analysis of the Thermodynamic Responses of In Situ Dielectric Spectroscopy Data in Amino Acids and Inorganic Electrolytes

et al. 2020

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“…For visual clarity, only the fits to the overall relaxation time traces (such as for SA3H) are shown. Furthermore, literature data on aqueous solutions of H 2 O 2 and N 2 H 4 (ref ) as well as of NH 3 (ref ) and KOH (ref ) are included. (b) T g,cal scaled Arrhenius plot of the motional correlation times that were determined using various NMR techniques (open symbols from diffusion data; filled symbols for τ < 10 –5 s from T 1 ; longer τ from F 2 ).…”

Section: Discussionmentioning

confidence: 99%

“…Apart from the data for the currently studied acid hydrates, in Figure a, we compile various relaxation time traces including those obtained at temperatures >250 K for pure water, , for aqueous KOH solution, for H 2 O 2 and N 2 H 4 hydrates, as well as for NH 3 solutions all of which were studied over wide composition ranges. For SA n H, an extrapolation of T g,ε on a 1/ n scale to 100% water content (i.e., n → 0) yields T g,ε = 135 ± 2 K closely matching the often quoted calorimetric glass transition temperature of low-density amorphous (LDA) ice.…”

Section: Discussionmentioning

confidence: 99%

“…For the present work, we examined the dynamical properties of several glass forming nitric and sulfuric acid hydrates using dielectric spectroscopy and various nuclear magnetic resonance (NMR) techniques. One of the motivations for our study is that mixtures of relatively simple (inorganic) water additives such as, e.g., N 2 H 4 , H 2 O 2 , NH 3 , or KOH, sometimes present only in subpercent amounts, are effective in suppressing the crystallization in the resulting aqueous solutions. The extent to which such studies can teach us something about the glass formation of H 2 O itself, a question which has been explored since long, is of vital importance in view of the ongoing debate regarding water’s glass transition with its numerous ramifications. ,− …”

Section: Introductionmentioning

confidence: 99%

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Dynamics in Glass Forming Sulfuric and Nitric Acid Hydrates

et al. 2013

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Deuteron nuclear magnetic resonance (NMR) and dielectric spectroscopy are utilized to investigate the dynamics in sulfuric acid hydrates as well as in nitric acid hydrates for various degrees of hydration. Near the glass transition temperature the electrical response is up to four decades faster than the calorimetric one, a feature found also for several other inorganic ionic liquids. The acid hydrates display pronounced super-Arrhenius behavior with fragility indices of the order of 100. The relaxation strength of the acid hydrates increases with increasing temperature, an observation that was rationalized with reference to the degree of molecular dissociation. Spin relaxometry and stimulated-echo spectroscopy revealed an overall isotropic reorientation process featuring a jump angle of about 30°. Finally, the implications of the present results for the understanding of the glass transition of pure ultraviscous water are discussed.

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Small-angle water reorientations in KOH doped hexagonal ice and clathrate hydrates

Nelson

Schildmann

Nowaczyk

et al. 2013

Phys. Chem. Chem. Phys.

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Using deuteron nuclear magnetic resonance and dielectric spectroscopy KOH doped tetrahydrofuran clathrate hydrates and KOH doped hexagonal ice are studied at temperatures above 60 and 72 K, respectively. Below these temperatures proton order is established on the lattice formed by the water molecules. In the clathrate hydrate a new type of small-angle motion is discovered using deuteron spin-spin relaxation, line-shape analysis, and stimulated-echo experiments. Based on the latter results a model is developed for the local proton motion that could successfully be tested using random-walk simulations. It is argued that the newly identified small-angle motion, obviously absent in undoped samples, is an important feature of the mechanism which accompanies the establishment of proton order not only in doped clathrate hydrates but also in doped hexagonal ice. Specific motions of OH(-) defects are demonstrated to explain the experimentally observed behavior. The relative importance of localized versus delocalized OH(-) defect motions is discussed.

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Salty Water in KOH-Doped Hexagonal Ice: a Proton and Deuteron NMR Study

Cited by 4 publications

References 44 publications

Machine Learning Analysis of the Thermodynamic Responses of In Situ Dielectric Spectroscopy Data in Amino Acids and Inorganic Electrolytes

Machine Learning Analysis of the Thermodynamic Responses of In Situ Dielectric Spectroscopy Data in Amino Acids and Inorganic Electrolytes

Dynamics in Glass Forming Sulfuric and Nitric Acid Hydrates

Small-angle water reorientations in KOH doped hexagonal ice and clathrate hydrates

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