Dielectric behavior of low boiling chlorides in the liquid, solid, and adsorbed states

1968 ◽  
Vol 46 (18) ◽  
pp. 2945-2957 ◽  
Author(s):  
T. McMullen ◽  
E. D. Crozier ◽  
R. McIntosh
Keyword(s):  
Sodium Chloride ◽  
Hydrogen Chloride ◽  
Surface Coverage ◽  
Dielectric Behavior ◽  
Dielectric Constants ◽  
Ethyl Chloride ◽  
Adsorbed Hydrogen ◽  
Adsorption Studies ◽  
Very High ◽  
Monolayer Coverage

The complex dielectric constants of hydrogen, methyl, and ethyl chlorides have been measured, for the purpose of comparison with the present and future adsorption studies. The hydrogen chloride results agree with those of Cole and Swensen (22). Studies of hydrogen and ethyl chlorides adsorbed on finely divided sodium chloride show two particularly interesting phenomena. Adsorbed hydrogen chloride shows an unusually high polarizability at monolayer surface coverage, which then decreases again with increasing adsorption. Adsorbed ethyl chloride also shows a very high polarizability at a particular surface coverage, but this maximum occurs at about one-fourth of monolayer coverage, and is accompanied by loss, in contrast to the former case.

THE DIELECTRIC BEHAVIOR AT LOW TEMPERATURES OF SEVERAL GASES ADSORBED UPON POROUS VYCOR GLASS

1962 ◽  
Vol 40 (1) ◽  
pp. 92-103 ◽  
Author(s):  
I. D. Chapman ◽  
R. McIntosh
Keyword(s):  
Low Temperatures ◽  
Molecular Layer ◽  
Dielectric Behavior ◽  
Dielectric Constants ◽  
Ethyl Chloride ◽  
Threshold Temperature ◽  
Hydroxyl Groups ◽  
Vycor Glass ◽  
Oh Groups ◽  
Adsorbed Phase

The complex dielectric constants of several systems comprising a gas adsorbed on Vycor glass have been measured at temperatures between 0 °C and −180 °C and frequencies between 3 kc/sec and 4 Mc/sec. The real and imaginary parts of the dielectric constant of the adsorbed phase have been computed. Loss maxima occurring at low temperatures are observed for some of the matter in the monolayer and are assumed to be due to complexes formed between the gas first admitted and hydroxyl groups which are covalently attached to the surface of the glass. The complexes may be considered either as dipoles having two equilibrium positions, or as highly damped oscillators. Ethyl chloride adsorbed in the first molecular layer and not bonded to OH behaves as an oscillatory system for which no loss is observed in the frequency and temperature ranges studied. Ethyl chloride adsorbed in the multilayers behaves similarly but shows a slightly greater temperature coefficient of ε′. Both these types of adsorbed ethyl chloride interact with the complexes and reduce the threshold temperature at which loss is observed in the complex. Methyl chloride interacts with OH groups in a similar fashion, but n-butane does not.

THE DIELECTRIC BEHAVIOR OF VAPORS ADSORBED ON SILICA GEL

1953 ◽  
Vol 31 (1) ◽  
pp. 72-83 ◽  
Author(s):  
J. A. Snelgrove ◽  
H. Greenspan ◽  
R. Mcintosh
Keyword(s):  
Temperature Coefficient ◽  
Silica Gel ◽  
Liquid State ◽  
Saturation Pressure ◽  
Adsorbed Water ◽  
Dielectric Behavior ◽  
Dielectric Constants ◽  
Ethyl Chloride ◽  
Oscillatory Motion ◽  
Molar Polarization

Experiments to determine the dielectric constants of adsorbed butane, ethyl chloride, and water on an activated silica at frequencies up to 3.7 Mc. per sec. are reported. No Debye-type dispersion was observed for the polar adsorbates down to −30 °C, the lowest temperature employed. Mixtures of ethyl chloride and water, and of butane and water, were also studied. The assumption that adsorption of ethyl chloride and water occurs with both adsorbates sharing two types of sites sufficed to explain the findings for this system. No explanation was apparent to account for the behavior of the butane–water system.Formulae due to Kurbatov and to Snelgrove and McIntosh have been used to interpret the results obtained with polar adsorbates. On the assumption that the adsorbates have densities equivalent to those for the liquid state at the same temperature, it is concluded that adsorbed water undergoes oscillatory motion. The first quantities of ethyl chloride adsorbed behave as though the molecules may rotate freely within an angle of 98°. The ethyl chloride adsorbed nearer the saturation pressure shows oscillatory motion, as a negligible temperature coefficient of the molar polarization is observed.

Tuning the Electric Field Response of MOFs by Rotatable Dipolar Linkers

2019 ◽  
Author(s):  
Johannes P. Dürholt ◽  
Babak Farhadi Jahromi ◽  
Rochus Schmid
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Structural Changes ◽  
Dielectric Behavior ◽  
Two Dimensions ◽  
Dielectric Constants ◽  
Electric Response ◽  
Dipole Strength ◽  
Metal Organic ◽  
Dynamics Simulations

Recently the possibility of using electric fields as a further stimulus to trigger structural changes in metal-organic frameworks (MOFs) has been investigated. In general, rotatable groups or other types of mechanical motion can be driven by electric fields. In this study we demonstrate how the electric response of MOFs can be tuned by adding rotatable dipolar linkers, generating a material that exhibits paralectric behavior in two dimensions and dielectric behavior in one dimension. The suitability of four different methods to compute the relative permittivity κ by means of molecular dynamics simulations was validated. The dependency of the permittivity on temperature T and dipole strength μ was determined. It was found that the herein investigated systems exhibit a high degree of tunability and substantially larger dielectric constants as expected for MOFs in general. The temperature dependency of κ obeys the Curie-Weiss law. In addition, the influence of dipolar linkers on the electric field induced breathing behavior was investigated. With increasing dipole moment, lower field strength are required to trigger the contraction. These investigations set the stage for an application of such systems as dielectric sensors, order-disorder ferroelectrics or any scenario where movable dipolar fragments respond to external electric fields.

Crystallization and dielectric properties of SrO–BaO–Nb2O5–GeO2 tungsten–bronze glass–ceramics

2001 ◽  
Vol 16 (7) ◽  
pp. 2057-2063 ◽  
Author(s):  
Jiin-Jyh Shyu ◽  
Hsin-Wei Peng
Keyword(s):  
Heat Treatment ◽  
Dielectric Properties ◽  
Tungsten Bronze ◽  
Glass Ceramics ◽  
Dielectric Behavior ◽  
Dendritic Morphology ◽  
Dielectric Constants ◽  
Two Stage ◽  
Tetragonal Tungsten Bronze ◽  
Stage Heat Treatment

The crystallization and dielectric properties of SrO–BaO–Nb2O5–GeO2 glass–ceramics were investigated. One- and two-stage heat-treatment methods were used to convert the parent glass to glass–ceramics. Strontium barium niobate (SBN) with a tetragonal tungsten-bronze structure formed as the major crystalline phase. When the crystallizing temperature/time was increased, the secondary crystalline BaGe2O5 phase coexisted with SBN. BaGe2O5 formed as a surface layer grown from the surface into the interior of the sample. The dendritic morphology of SBN crystals was examined. The glass–ceramics crystallized by two-stage heat treatment have higher dielectric constants than those crystallized by one-stage heat treatment. The highest dielectric constant that was obtained in the present glass–ceramics was 320. The glass–ceramics showed relaxor-type dielectric behavior.

scholarly journals The behaviour of electrolytes in mixed solvents. Part I.—The free energies and heat contents of hydrogen chloride in water—Ethyl alcohol solutions

1929 ◽  
Vol 125 (799) ◽  
pp. 694-712 ◽  
Keyword(s):  
Hydrogen Chloride ◽  
Electric Fields ◽  
Mixed Solvents ◽  
Dielectric Constants ◽  
Free Energies ◽  
Dissolved Ions ◽  
Uniform Medium ◽  
The Mean ◽  
Solvent Molecules ◽  
Water Alcohol

Previous studies on the effect of a change of medium on tire properties of dissolved electrolytes have aimed at correlating the behaviour of the electrolyte with the mean physical properties, e. g ., dielectric constants, of the medium. While this approach may be justified in the case of solvents containing molecules of only one kind, it is not sufficient to regard a mixed solvent as a uniform medium affecting the dissolved ions solely through the effect of its dielectric constant on the electric forces between them. For the electric fields of ions exert a differential attraction on molecules possessing different degrees of polarisability and since tire more polarisable molecules must tend to congregate round the ions, the properties of the latter cannot depend solely on tire mean properties of tire medium. Studies on the behaviour of ions in such cases will throw light on the interaction between ions and solvent molecules. The present paper gives tire results of measurements of the free energies and heat contents of hydrogen chloride in water-alcohol solutions, obtained by determining the electromotive forces of cells of the type:— H 2 ( g ) | HCl ( m ), AgCl ( s ) | Ag water-alcohol

Plasma Enhanced Mocvd of BaTiO3 Films

1991 ◽  
Vol 243 ◽  
Author(s):  
Peter C. Van Buskirk ◽  
Robin Gardiner ◽  
Peter S. Kirlin ◽  
Salora Krupanidhi ◽  
Steven Nutt
Keyword(s):  
Single Phase ◽  
Chemical Vapor ◽  
Dielectric Constants ◽  
Polycrystalline Films ◽  
Fine Grained ◽  
Selected Area Electron Diffraction ◽  
Electro Optic ◽  
Ir Reflectance ◽  
High Dielectric ◽  
Very High

AbstractBulk BaTiO3 has a large linear electro-optic coefficient and a very high dielectric constant. We report results obtained for two different MOCVD processes designed to deposit BaTiO3 films with properties suitable for nonlinear electro-optic or high charge storage applications. Epitaxial BaTiO3 films have been grown on NdGaO3 [100] substrates using a high temperature thermal process; the substrate temperature was 1000°C and the total pressure was 4 torr. Selected area electron diffraction (SAED) measurements indicate highly textured, single phase films on the NdGaO3 substrate which are predominantly [100] oriented. Fine grained polycrystalline films have been grown on Pt at 600°C by plasma-enhanced metalorganic chemical vapor deposition (PEMOCVD). Specular IR reflectance was used to determine the concentration of BaCO3 in the film, which was significantly reduced by the plasma. The polycrystalline films had dielectric constants as large as 300 and resistivities exceeding 5 x 108 Ω-cm at room temperature.

A simplified form of Stokes–Robinson equation

1976 ◽  
Vol 54 (1) ◽  
pp. 9-11 ◽  
Author(s):  
Chai-Fu Pan
Keyword(s):  
Sodium Chloride ◽  
Hydrogen Chloride ◽  
Activity Coefficients ◽  
Aqueous Electrolyte ◽  
Electrolyte Solutions ◽  
Solvent Interactions ◽  
Interionic Interactions ◽  
Two Parameter ◽  
Robinson Equation ◽  
Existing Data

In non-associated dilute aqueous electrolyte solutions, the deviation from ideality is principally attributed to the interionic interactions and hydration of ions. Stokes and Robinson combined Bjerrum's thermodynamic treatment of ion–solvent interactions with Debye–Hückel treatment of interionic interactions to obtain a two-parameter equation. In very dilute regions, the Stokes and Robinson's equation reduces to a much simpler form, i.e.[Formula: see text]Activity coefficients of an electrolyte at lower concentrations, say up to 0.1 m, can be calculated from the equation provided suitable values of &([a-z]+); and h are available. Solutions of hydrogen chloride and sodium chloride were chosen as examples. The results agree with the existing data very satisfactorily.

PRELIMINARY OBSERVATIONS OF THE DIELECTRIC CONSTANTS OF VAPORS ADSORBED ON ACTIVATED SILICA

1947 ◽  
Vol 25b (6) ◽  
pp. 566-574 ◽  
Author(s):  
R. McIntosh ◽  
L. McLeod ◽  
H. S. Johnson ◽  
N. Hollies
Keyword(s):  
Dielectric Constant ◽  
Ethylene Oxide ◽  
Silica Gel ◽  
Dielectric Constants ◽  
Ethyl Chloride ◽  
Bulk Liquid ◽  
Temperature Coefficients ◽  
Capacity Change

A measure of the dielectric constants of several substances adsorbed on silica gel has been obtained by measuring the change in the capacity of an electrical condenser when measured amounts of the substances were adsorbed on silica gel situated between the plates of the condenser. The substances examined were ethyl chloride, n-butane, and ethylene oxide. The plot of capacity change vs. amount adsorbed was found, in all cases, to consist of two or more quite distinct sections, each approximating to linearity. The temperature coefficients of dielectric constant were evaluated. The dielectric constant calculated for adsorbed n-butane was close to that calculated for the bulk liquid, whereas the value calculated for adsorbed ethyl chloride was significantly lower than the value calculated for the liquid.

AN APPARATUS FOR THE MEASUREMENT OF DIELECTRIC CONSTANTS OF ADSORBED GASES AT FREQUENCIES UP TO 100 Mc./Sec.

1955 ◽  
Vol 33 (2) ◽  
pp. 268-278 ◽  
Author(s):  
M. H. Waldman ◽  
R. McIntosh
Keyword(s):  
Sulphur Dioxide ◽  
Experimental Error ◽  
Dielectric Behavior ◽  
Dielectric Constants ◽  
Frequency Range

The design of an apparatus suitable for the measurement of dielectric constants at frequencies up to 106 Mc./sec. is shown. The apparatus was used to measure changes in capacitance with volume adsorbed for the system sulphur dioxide – rutile at about 3.5 °C. and for frequencies of 13, 36, and 106 Mc./sec. The results failed to reveal any dispersion due to the adsorbed matter in this frequency range. The dielectric behavior observed is the same, within experimental error of a few per cent, as that found by Channen and McIntosh for the same system at 3.7 Mc./sec.

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