diffusion current

diffusion current

[də′fyü·zhən ‚kər·ənt]
(analytical chemistry)
In polarography with a dropping-mercury electrode, the flow that is controled by the rate of diffusion of the active solution species across the concentration gradient produced by the removal of ions or molecule at the electrode surface.
References in periodicals archive ?
The transfer characteristics of MOSFET exemplify that the diffusion current governs the subthreshold region, while the drift current dominates in the linear-saturation region.
The elimination function is based on rate dependence of various currents, that is, diffusion current, kinetic current, charging current, and so forth.
If the electron and hole densities are assumed to be equal, then 2/D = 1/[D.sub.n] + 1/[D.sub.p], which means that the ambipolar diffusion current is the sum of electrons and holes.
Due to anisotropy and the large ratio of [[rho].sub.[101]]/[[rho].sub.(101)], the diffusion current along [101] axis is much larger than that along the [101] axis.
Where ai and aA are the ratios of diffusion current at concentrations of interfering agent and analyte respectively.
In this method, the diffusion current is proportional to the concentration of the substance, and a change in the concentration to be determined is immediately reflected in the value of diffusion current [4-6].
where [i.sup.[alpha]] means a partial density vector of diffusion current, e[rho]--space charge, i--total density of diffusion current.
The principle of this method consists of measuring the limiting diffusion current at the cathode of an electrolysis cell during an electrochemical reaction, so as to determine the mass transfer rate.
The temperature coefficient values of diffusion current as shown in Table 1 and 2 are found to be between 1.00 to 1.56% per degree which is in agreement with the range predicted by Meites for organic molecules (Meites,1967).
These criteria are based on the polarographic diffusion current [i.sub.d], currents at defined voltages on the rising portion of the polarographic wave, i, and the adjusted mercury head above the dropping mercury electrode, h.
In all the cases decrease in diffusion current occurred with increasing ligand concentration.
This removes the need to evaluate ionic currents and diffusion currents at millions of sites, and allows the use of a much lower spatial resolution (in the order of 1 mm).

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