The dependence of the rate of electrochemical charge transfer on the electric field at the metal-electrolyte interface

1972 ◽  
Vol 25 (2) ◽  
pp. 231 ◽  
Author(s):  
DB Matthews
Keyword(s):  
Electron Transfer ◽  
Charge Transfer ◽  
Potential Energy ◽  
Electric Field ◽  
Electric Fields ◽  
Potential Energy Curves ◽  
Energy Curve ◽  
Electrolyte Interface ◽  
Activated State ◽  
Wide Range

Electric fields at the metal-electrolyte interface are very high (of the order of 107 V/cm) and one intuitively expects that these fields should have a profound influence on the movement of charged species such as ions and electrons at the interface. Qualitatively, such field effects manifest themselves as deviations from linearity of Tafel plots or as a dependence of the symmetry factor on electrode potential. It is shown that Gurney's potential energy curve representation of charge transfer reactions yields only small changes in β over a wide range of potential, with the anharmonic (Morse) curves showing smaller changes than the harmonic (parabolic) curves. Superposition of the double layer electric field on these potential energy curves increases the curvature of the Tafel plots, but the effect is still not very large, being within the limits of uncertainty in determining the correct form of the potential energy curves. The effect of electric field on electron transfer is considered both from the viewpoint of change in electron transfer distance arising from a dependence of coordinates of the activated state on potential and from the viewpoint of a direct effect on the electron transfer barrier (analogous to field electron emission). The field emission effects are found to be even less than the effects of the field on the proton transfer potential energy barrier.

The dependence of the photocurrent at the metal-electrolyte interface on electrode potential

1975 ◽  
Vol 28 (2) ◽  
pp. 253 ◽  
Author(s):  
DB Matthews ◽  
SUM Khan
Keyword(s):  
Electron Transfer ◽  
Charge Transfer ◽  
Potential Energy ◽  
Physical Interpretation ◽  
Linear Dependence ◽  
Energy Barrier ◽  
Electrode Potential ◽  
Potential Energy Barrier ◽  
Electrolyte Interface ◽  
Solvent Molecules

The Gurney theory of charge transfer at the metal-electrolyte interface is extended to the case of photoemission. It is found that the simple Gurney model is not sufficient to explain the results observed by a number of independent workers. In order to explain the observed linear dependence of the 0.4 power of the photocurrent on electrode potential it is found necessary to allow explicitly for the existence of a layer of solvent molecules at the metal surface. This layer of molecules con- stitutes a potential energy barrier to electron transfer with a width of about 0.28 nm and a height (with respect to the Fermi level of the metal) of about 560 kJ mol-1 for water. The model is geometrically quite similar to that used in the very successful Brodsky model but differs in physical interpretation of the surface potential energy barrier.

scholarly journals Restraining Surface Charge Accumulation and Enhancing Surface Flashover Voltage through Dielectric Coating

Coatings ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 750
Author(s):  
Jixing Sun ◽  
Sibo Song ◽  
Xiyu Li ◽  
Yunlong Lv ◽  
Jiayi Ren ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Electric Field ◽  
Electric Fields ◽  
Transition Process ◽  
Metallic Particle ◽  
Particle Charging ◽  
Insulating Surfaces ◽  
Surface Flashover ◽  
Charging Time ◽  
The Impact

A conductive metallic particle in a gas-insulated metal-enclosed system can charge through conduction or induction and move between electrodes or on insulating surfaces, which may lead to breakdown and flashover. The charge on the metallic particle and the charging time vary depending on the spatial electric field intensity, the particle shape, and the electrode surface coating. The charged metallic particle can move between the electrodes under the influence of the spatial electric field, and it can discharge and become electrically conductive when colliding with the electrodes, thus changing its charge. This process and its factors are mainly affected by the coating condition of the colliding electrode. In addition, the interface characteristics affect the particle when it is near the insulator. The charge transition process also changes due to the electric field strength and the particle charging state. This paper explores the impact of the coating material on particle charging characteristics, movement, and discharge. Particle charging, movement, and charge transfer in DC, AC, and superimposed electric fields are summarized. Furthermore, the effects of conductive particles on discharge characteristics are compared between coated and bare electrodes. The reviewed studies demonstrate that the coating can effectively reduce particle charge and thus the probability of discharge. The presented research results can provide theoretical support and data for studying charge transfer theory and design optimization in a gas-insulated system.

The vibration of electrified water drops

1971 ◽  
Vol 322 (1551) ◽  
pp. 523-534 ◽  
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Axial Ratio ◽  
Uniform Electric Field ◽  
Interferometric Technique ◽  
Photographic Analysis ◽  
Wide Range ◽  
Water Drops ◽  
Strength And Deformation ◽  
A Charge

Pressure has been used as the principal parameter in calculations of the fundamental vibrational frequencies of spherical drops of radius R , density ρ, and surface tension T carrying a charge Q or uncharged spheroidal drops of axial ratio a / b situated in a uniform electric field of strength E . Freely vibrating charged drops have a frequency f = f 0 ( 1 - Q 2 /16π R 3 T ) ½ , as shown previously by Rayleigh (1882) using energy considerations; f 0 is the vibrational frequency of non-electrified drops (Rayleigh 1879). The fundamental frequency of an uncharged drop in an electric field will decrease with increasing field strength and deformation a / b and will equal zero when E ( R )/ T ) ½ = 1.625 and a / b = 1.86; these critical values correspond to the disintegration conditions derived by Taylor (1964). An interferometric technique involving a laser confirmed the accuracy of the calculations concerned with charged drops. The vibration of water drops of radius around 2 mm was studied over a wide range of temperatures as they fell through electric fields either by suspending them in a vertical wind tunnel or allowing them to fall between a pair of vertical electrodes. Photographic analysis of the vibrations revealed good agreement between theory and experiment over the entire range of conditions studied even though the larger drops were not accurately spheroidal and the amplitude of the vibrations was large.

scholarly journals Improving of electrical channels for magnetotelluric sounding instrumentation

2015 ◽  
Vol 4 (2) ◽  
pp. 149-154 ◽  
Author(s):  
A. M. Prystai ◽  
V. O. Pronenko
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Deep Structure ◽  
Experimental Tests ◽  
Magnetotelluric Sounding ◽  
Earth’S Crust ◽  
Geomagnetic Variations ◽  
The Earth ◽  
Wide Range ◽  
Earth's Crust

Abstract. The study of the deep structure of the Earth's crust is of great interest for both applied (e.g. mineral exploration) and scientific research. For this the electromagnetic (EM) studies which enable one to construct the distribution of electrical conductivity in the Earth's crust are of great use. The most common method of EM exploration is magnetotelluric sounding (MT). This passive method of research uses a wide range of natural geomagnetic variations as a powerful source of electromagnetic induction in the Earth, producing telluric current variations there. It includes the measurements of variations of natural electric and magnetic fields in orthogonal directions at the surface of the Earth. By this, the measurements of electric fields are much more complicated metrological processes, and, namely, they limit the precision of MT prospecting. This is especially complicated at deep sounding when measurements of long periods are of interest. The increase in the accuracy of the electric field measurement can significantly improve the quality of MT data. Because of this, the development of a new version of an instrument for the measurements of electric fields at MT – both electric field sensors and the electrometer – with higher levels relative to the known instrument parameter level – was initiated. The paper deals with the peculiarities of this development and the results of experimental tests of the new sensors and electrometers included as a unit in the long-period magnetotelluric station LEMI-420 are given.

Two-phase GaAs cermet-gate charge-coupled devices

1991 ◽  
Vol 69 (3-4) ◽  
pp. 224-228
Author(s):  
M. LeNoble ◽  
J. V. Cresswell ◽  
R. R. Johnson
Keyword(s):  
Charge Transfer ◽  
Electric Field ◽  
Electric Fields ◽  
Two Phase ◽  
Charge Coupled Device ◽  
Charge Coupled Devices ◽  
Band Limited ◽  
Gate Charge

A nonplanar 64-pixel, 2-phase GaAs cermet-gate charge-coupled device (CMCCD) and a planar 128-pixel, 2-phase GaAs CMCCD are described. The former device employs a castellation to provide the "built-in" electric field for controlling the flow of signal charge within the channel, whereas, the latter device uses externally applied electric fields to achieve this control. Both devices have been operated at 46 MHz, demonstrating charge transfer efficiencies of 0.996 and in excess of 0.999, respectively. The application of the planar 2-phase GaAs CMCCD in a 500 or 7.81 MHz transient digitizer module for acquisition and transfer of dc to 250 MHz band-limited signals will also be presented.

The Absence of a Marcus Inversion Region for Electron Transfer at the Metal-Redox Electrolyte Interface

1994 ◽  
Vol 47 (12) ◽  
pp. 2171 ◽  
Author(s):  
D Matthews
Keyword(s):  
Electron Transfer ◽  
Potential Energy ◽  
Electron Distribution ◽  
Distribution Functions ◽  
Rate Distribution ◽  
Inversion Region ◽  
Redox Electrolyte ◽  
Electrolyte Interface ◽  
Metal Redox ◽  
Nuclear Configuration

The theory of electron transfer at the metal- redox electrolyte interface is described by starting with the work of Gurney and incorporating that of Gerischer and Marcus. This GGM model brings together diverse approaches to the description of electron transfer at electrodes. The electron transfer is described in terms of nuclear configuration potential energy diagrams, electronic configuration potential energy diagrams, electron distribution functions and rate distribution functions. The distinction between microscopic energies and macroscopic (thermodynamic) energies is made and the concept of the Fermi level of the redox electrolyte is clarified. The model of identical parabolas is used for the nuclear configuration diagrams and this is shown to lead to Gaussian electron distribution functions for the redox electrolyte. The rate distribution is obtained from the overlap between occupied and unoccupied states of the metal and redox electrolyte. Integration of the rate distribution gives the rate which is calculated as a function of the electrode potential for various values of the reorganization energy λ. It is shown that the variation of symmetry factor β is small for high λ and that the Tafel plots do not show significant decrease in rate at high overpotentials in the anomalous or inversion region. The Tafel plots for charge transfer (mass transfer is assumed to be fast at all potentials) tend to a limiting value with only a small decrease at high overpotential. This contrasts with the prediction based on nuclear configuration potential energy curves and is attributed to the fact that the overlap is between a Gaussian and a Fermi function rather than between two Gaussians, the latter being the case for homogeneous reactions.

Tuning the inter-molecular charge transfer, second-order nonlinear optical and absorption spectra properties of a π-dimer under an external electric field

2017 ◽  
Vol 19 (47) ◽  
pp. 31958-31964 ◽  
Author(s):  
Feng-Wei Gao ◽  
Hong-liang Xu ◽  
Zhong-Min Su
Keyword(s):  
Charge Transfer ◽  
Electric Field ◽  
Electric Fields ◽  
Nonlinear Optical ◽  
Stability Control ◽  
External Electric Fields ◽  
Optical Responses ◽  
Molecular Charge ◽  
Spectra Properties ◽  
The Stability

Different strengths of external electric fields enhance the stability, control the inter-molecular charge transfer and strengthen the nonlinear optical responses of a π-dimer.

The mechanism of charge transfer at electrodes

1966 ◽  
Vol 292 (1431) ◽  
pp. 479-488 ◽  
Keyword(s):  
Electron Transfer ◽  
Charge Transfer ◽  
Quantum Mechanical ◽  
General Applicability ◽  
Classical Electron ◽  
Transfer Processes ◽  
Symmetry Factor ◽  
Activated State ◽  
Resonance Nature

A detailed theoretical investigation of the roles played by classical electron transfer, quantum mechanical electron transfer and classical proton transfer led to the formulation of a new mechanism of charge transfer in the discharge step of the hydrogen evolution re­ action. The mechanism of charge transfer was shown to have general applicability to charge transfer processes at electrodes. The theory led to the recognition of the resonance nature of the activated state, to the determination of the charge distribution in the activated state, and to a better physical understanding of the symmetry factor, β, in electrode kinetics.

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