scholarly journals A NMR Spin-Echo Study of Diffusion in Molten Salts

2004 ◽  
Vol 59 (1-2) ◽  
pp. 51-58 ◽  
Author(s):  
Günter Palmer ◽  
Joachim Richter ◽  
Manfred D. Zeidler
Keyword(s):  
High Pressure ◽  
Titanium Alloy ◽  
Diffusion Coefficients ◽  
High Frequency ◽  
Molten Salts ◽  
Pressure Range ◽  
Spin Echo ◽  
Ambient Pressure ◽  
Pressure Probe ◽  
Self Diffusion

Pressure-dependent measurements of the cationic self-diffusion coefficients of molten (Na, Li)NO3 were carried out at 613 K. The pressure range lies between ambient pressure and 200 MPa. A new high-pressure probe, operating with heating coils, was constructed from titanium alloy. The temperature difference across the probe could be confined to 2.5 K. By use of a switchable high-frequency coil the nuclei lithium and sodium could be measured in succession within the same sample. The activation volumes are composition-dependent and range from 5 to 9 cm3mol−1.

scholarly journals An NMR Spin-Echo Study of Diffusion in a Room-Temperature Molten Salt

2004 ◽  
Vol 59 (1-2) ◽  
pp. 59-63 ◽  
Author(s):  
Günter Palmer ◽  
Joachim Richter ◽  
Manfred D. Zeidler
Keyword(s):  
High Pressure ◽  
Molten Salt ◽  
Diffusion Coefficients ◽  
Pressure Range ◽  
Room Temperature ◽  
Spin Echo ◽  
Ambient Pressure ◽  
The Self ◽  
Pressure Probe ◽  
Self Diffusion

Pressure-dependent measurements of self-diffusion in the room-temperature molten salt (RTMS) N,N-butylmethylimidazoliumhexafluorophosphate were carried out at 298 and 308 K. The pressure range lied between ambient pressure and 300 MPa. In addition, methanolic solutions of this RTMS were investigated at ambient pressure. The self-diffusion coefficients of both components are reported as functions of concentration and temperature in the range 293 - 313 K. A modified version of a recently published high-pressure probe is described.

Spin Echo Self-Diffusion Measurements in Molten Salts

1988 ◽  
Vol 43 (12) ◽  
pp. 1075-1082 ◽  
Author(s):  
C. Herdlicka ◽  
J. Richter ◽  
M. D. Zeidler
Keyword(s):  
Magnetic Field ◽  
Diffusion Coefficients ◽  
Molten Salts ◽  
Spin Echo ◽  
Pulsed Magnetic Field ◽  
Self Diffusion ◽  
Field Gradients ◽  
Magnetic Field Gradients ◽  
Spin Echo Technique ◽  
Probe Head

An NMR probe head for diffusion measurements in molten salts at temperatures up to 673 K is described. The spin echo technique using pulsed magnetic field gradients was employed. Resulting self-diffusion coefficients of Na+ in molten NaNO3 in the temperature range 596-670 K are compa­red with literature data obtained by other methods.

scholarly journals Theoretical Modelling of Ion Exchange Processes in Glass: Advances and Challenges

2021 ◽  
Vol 11 (11) ◽  
pp. 5070
Author(s):  
Xesús Prieto-Blanco ◽  
Carlos Montero-Orille
Keyword(s):  
Ion Exchange ◽  
Diffusion Coefficients ◽  
Molten Salts ◽  
Theoretical Modelling ◽  
Copper Films ◽  
Theoretical Frameworks ◽  
Self Diffusion ◽  
Exchange Processes ◽  
The One ◽  
Made In

In the last few years, some advances have been made in the theoretical modelling of ion exchange processes in glass. On the one hand, the equations that describe the evolution of the cation concentration were rewritten in a more rigorous manner. This was made into two theoretical frameworks. In the first one, the self-diffusion coefficients were assumed to be constant, whereas, in the second one, a more realistic cation behaviour was considered by taking into account the so-called mixed ion effect. Along with these equations, the boundary conditions for the usual ion exchange processes from molten salts, silver and copper films and metallic cathodes were accordingly established. On the other hand, the modelling of some ion exchange processes that have attracted a great deal of attention in recent years, including glass poling, electro-diffusion of multivalent metals and the formation/dissolution of silver nanoparticles, has been addressed. In such processes, the usual approximations that are made in ion exchange modelling are not always valid. An overview of the progress made and the remaining challenges in the modelling of these unique processes is provided at the end of this review.

Self-Diffusion in Molten Lithium Nitrate

1992 ◽  
Vol 47 (10) ◽  
pp. 1047-1050 ◽  
Author(s):  
C. Herdlicka ◽  
J. Richter ◽  
M. D. Zeidler
Keyword(s):  
Diffusion Coefficient ◽  
Diffusion Coefficients ◽  
Spin Echo ◽  
The Self ◽  
Lithium Nitrate ◽  
Equimolar Ratio ◽  
Self Diffusion ◽  
Field Gradients ◽  
Molten Lithium ◽  
Self Diffusion Coefficient

AbstractSelf-diffusion coefficients of 7Li+ ions have been measured in molten LiNO3 with several compositions of 6Li+ and 7Li+ over a temperature range from 537 to 615 K. The NMR spin-echo method with pulsed field gradients was applied. It was found that the self-diffusion coefficient depends on the isotopic composition and shows a maximum at equimolar ratio. At temperatures above 600 K this behaviour disappears.

Self-diffusion, velocity cross-correlation, distinct diffusion and resistance coefficients of the ionic liquid [BMIM][Tf2N] at high pressure

2015 ◽  
Vol 17 (37) ◽  
pp. 23977-23993 ◽  
Author(s):  
Kenneth R. Harris ◽  
Mitsuhiro Kanakubo
Keyword(s):  
High Pressure ◽  
Ionic Liquid ◽  
Transport Properties ◽  
Diffusion Coefficients ◽  
Cross Correlation ◽  
Diffusion Velocity ◽  
Self Diffusion ◽  
Scaling Parameters ◽  
Resistance Coefficients ◽  
Viscosity Dependence

Distinct diffusion coefficients for 1-alkyl-3-imidazolium [Tf2N] salts show very similar viscosity dependence; thermodynamic scaling parameters for the reduced transport properties are equal.

PGSE-NMR & Sans from TPB Based Microemulsions

1989 ◽  
Vol 177 ◽  
Author(s):  
Paul M. Lindemuth ◽  
Boualem Hammouda ◽  
Joseph R. Duke ◽  
Frank D. Blum ◽  
Raymond L. Venable
Keyword(s):  
Diffusion Coefficients ◽  
Small Angle Neutron Scattering ◽  
Spin Echo ◽  
Water Concentration ◽  
Conductivity Measurements ◽  
Self Diffusion ◽  
Nmr Data ◽  
Pgse Nmr ◽  
Isotropic Region ◽  
Complete Inversion

ABSTRACTSelf-diffusion coefficients from pulsed-gradient spin-echo NMR are reported for four components of the tetradecylpyridinium bromide - 85% heptane/15% pentanol - water pseudoternary system. Measurements were taken throughout the inverted microemulsion region and also in a small isotropic region beyond the domain of lamellar liquid crystals. Observations of the self-diffusion coefficients for water relative to those of the surfactant, oil and alchohol show several distinct structural transitions within the water-in-oil region of the phase diagram. The smaller isotropic region exhibits a complete inversion of phase relative to the water-in-oil region. Conductivity measurements were used to further clarify the NMR data. Subsequent small angle neutron scattering (SANS) measurements on the same system show the transition from the single particle (heavy water + Stern layer droplet) scattering regime at low water concentration to the mixed single/interdroplet scattering regime when the intermicellar distance becomes comparable to the size of the micelles.

DC Magnetic Susceptibility of CeCoGe2.36Si0.64 under High Pressure

2012 ◽  
Vol 190 ◽  
pp. 405-408
Author(s):  
J.J. Larrea ◽  
J. Teyssier ◽  
H. Ronnow ◽  
M. Müller ◽  
A. Sidorenko ◽  
...  
Keyword(s):  
High Pressure ◽  
Magnetic Susceptibility ◽  
Heavy Fermion ◽  
Pressure Range ◽  
Magnetic Phase ◽  
Ambient Pressure ◽  
Quantum Critical Point ◽  
Magnetic Phase Diagram ◽  
Antiferromagnetic Order

We report an investigation of the magnetic phase diagram of the heavy fermion com-pound CeCoGe2.36Si0.64 using DC magnetic susceptibility measurements under high pressure upto 10 kbar. The antiferromagnetic order that develops at ambient pressure below about 5.5 Kremains essentially unaffected by pressure in the investigated pressure range up to 10 kbar. Onthe other hand, moderate magnetic fields appear to induce a quantum critical point in a sam-ple subject to a pressure of 2 kbar. We discuss the role of disorder in the series of compoundsCeCoGe3−xSix.

scholarly journals Negative Pressure Regimes in Ionic Liquids: Structure and Interactions in Stretched Liquids as Probed by NMR

2018 ◽  
Author(s):  
Luis Paulo Rebelo
Keyword(s):  
Ionic Liquids ◽  
Negative Pressure ◽  
Diffusion Coefficients ◽  
Sharp Increase ◽  
Molten Salts ◽  
Structure And Properties ◽  
Saturated Liquid ◽  
Nmr Studies ◽  
Preliminary Testing ◽  
Self Diffusion

In this work, a broad pallete of macroscopically sized samples of ionic liquids was used, in which tensions of about -100 MPa were obtained in preliminary testing methodologies before cavitation would occur. Preliminary NMR studies have been performed on ionic liquids under homogeneous tension. Upon entering into these metastable regimes of negative pressure, it is possible to observe a sharp increase in the anion and cation self-diffusion coefficients as compared to the equilibrium saturated liquid conditions at identical temperatures. [L02 - Molten Salts and Ionic Liquids 21, Structure and Properties I, Tuesday, October 2nd, 10:40, #1832-AiMES2018, Universal 9 – Abstract Oral #116064 ]

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