Deep ultraviolet and visible crystalloluminescence of sodium chloride

Alexander, Andrew J.

doi:10.1063/1.3684548

Cited by 14 publications

(16 citation statements)

References 34 publications

(60 reference statements)

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“…The free monomer ions are in a very different electric environment than those in metastable clusters or the crystal, indicating a gradual coordination transformation from fully hydrated free monomer ions, to partially hydrated metastable clusters, and then to the fully dehydrated crystal. The Cl − ion average potential increases almost linearly from free ions → clusters → bulk crystal, with a difference in an average potential of ⟨V(Cl − )⟩ 4 3 − ⟨V(Cl − )⟩ free ion = + 240 mV = +5.52 kcal/mol. In contrast, the Na + ion average potential decreases starting from the free ions to the clusters; however, it must reach a minimum and then increase to reach the bulk crystal limit, with a difference in an average potential of ⟨V(Na + )⟩ 4 3 − ⟨V(Na + )⟩ free ion = − 110 mV = −2.53 kcal/mol.…”

Section: ■ Resultsmentioning

confidence: 99%

“…The Cl − ion average potential increases almost linearly from free ions → clusters → bulk crystal, with a difference in an average potential of ⟨V(Cl − )⟩ 4 3 − ⟨V(Cl − )⟩ free ion = + 240 mV = +5.52 kcal/mol. In contrast, the Na + ion average potential decreases starting from the free ions to the clusters; however, it must reach a minimum and then increase to reach the bulk crystal limit, with a difference in an average potential of ⟨V(Na + )⟩ 4 3 − ⟨V(Na + )⟩ free ion = − 110 mV = −2.53 kcal/mol. For comparison, we also show the average interior ion potentials for the bulk crystal to indicate how much the ions' potentials change between the free ions, metastable clusters, and when they are within the interior of a bulk crystal.…”

Section: ■ Resultsmentioning

confidence: 99%

“…Finally, we turn to the composition and charge states of the metastable clusters shown in Figure . Here, we exclude, by nature of the classical model employed in our simulations, the possibility of these intense fields inducing charge transfer, non-adiabaticity, or radicalization during the clustering underlying nucleation of NaCl even though there is experimental measurements of crystalloluminescence, piezoluminescence, lyoluminescence, and theoretical evidence that this may indeed occur including the role of trace impurities undergoing radicalization. ,,,, Here, we explore the commonly invoked assumption of charge neutral pathways by addressing the following questions: are charged pathways relevant to metastable clusters and, if so, is there a sign preference? In general, cluster evolution can also include free ion or odd-sized cluster addition and loss.…”

Section: Resultsmentioning

confidence: 99%

“…Nucleation is the first step in aqueous salt formation where small metastable clusters of ions form as precursors of the new phase. Nucleation and crystallization processes are influenced by many factors including internal and external electric potentials and fields (e.g., fast amorphous-to-crystalline transitions in phase-change memory applications, field-induced crystallization, and the emission of visible, UV, and deep-UV light called crystalloluminescence , ). It has also been shown that the formation of small ionic clusters can generate new interfaces with the solvent, and the resulting interfacial fields are strong enough to break bonds, distort molecules, and induce ionization or radicalization. , However, to the best knowledge of the authors, there are no studies quantifying and classifying the distributions of electric potentials and fields experienced by free ions, ions in metastable clusters, and ions in finite crystals.…”

Section: Introductionmentioning

confidence: 99%

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Electric Potentials of Metastable Salt Clusters

et al. 2019

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Electric potentials and fields experienced by the ions in small metastable NaCl clusters and cubic crystals in vacuum and aqueous electrolyte solutions are used to characterize features underlying condensed-phase nucleation. The range of electrostatic potentials and fields experienced by NaCl nanocrystals and metastable clusters is analyzed using point charges and quantified as a function of particle size and charge state. We show how the potentials and fields of these crystals can be classified into various subgroups corresponding to corners, edges, faces, and interior sites. The differences between the interior and face potentials are correlated with the interfacial surface energy. This, in turn, influences cluster free energies and their corresponding populations in solution. As a result, the nucleation rate is correlated to these potentials through the formalism of classical nucleation theory. Additionally, we consider the importance of representation of the charge density, comparing point charge and continuous densities obtained from the quantum mechanical electronic structure. A key result of this work is the identification of the electric potential as a possible order parameter to understand nucleation pathways.

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Section: ■ Resultsmentioning

confidence: 99%

Section: ■ Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Electric Potentials of Metastable Salt Clusters

et al. 2019

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“…Similarly, the crushing of such ordinary materials such as white crystalline sugar will induce flashes of luminescence [ 11 , 12 ], because bonds are disrupted and the energy is partially dissipated as light. That chemical bonds play important roles in the luminescent properties of certain solids is further exemplified by the fact that photons may equally be produced during crystallization processes [ 13 , 14 ] in which atoms take their place at certain positions in the crystal lattice and bonds are formed. This form of luminescence is aptly called crystalloluminescence.…”

Section: Introductionmentioning

confidence: 99%

Fluorescent Probes and Fluorescence (Microscopy) Techniques — Illuminating Biological and Biomedical Research

Drummen¹

2012

Molecules

120

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Fluorescence, the absorption and re-emission of photons with longer wavelengths, is one of those amazing phenomena of Nature. Its discovery and utilization had, and still has, a major impact on biological and biomedical research, since it enables researchers not just to visualize normal physiological processes with high temporal and spatial resolution, to detect multiple signals concomitantly, to track single molecules in vivo, to replace radioactive assays when possible, but also to shed light on many pathobiological processes underpinning disease states, which would otherwise not be possible. Compounds that exhibit fluorescence are commonly called fluorochromes or fluorophores and one of these fluorescent molecules in particular has significantly enabled life science research to gain new insights in virtually all its sub-disciplines: Green Fluorescent Protein. Because fluorescent proteins are synthesized in vivo, integration of fluorescent detection methods into the biological system via genetic techniques now became feasible. Currently fluorescent proteins are available that virtually span the whole electromagnetic spectrum. Concomitantly, fluorescence imaging techniques were developed, and often progress in one field fueled innovation in the other. Impressively, the properties of fluorescence were utilized to develop new assays and imaging modalities, ranging from energy transfer to image molecular interactions to imaging beyond the diffraction limit with super-resolution microscopy. Here, an overview is provided of recent developments in both fluorescence imaging and fluorochrome engineering, which together constitute the “fluorescence toolbox” in life science research.

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