apex current

In measurement of non-faradaic admittance (or tensammetry), a plot of alternating current against applied potential shows a minimum or maximum when a non-electroactive substance undergoes adsorption or desorption at the surface of the indicator electrode. Such a maximum or minimum may be called an apex to emphasize its non-faradaic origin and distinguish it from a 'summit', which would result from a charge-transfer process. The highest value of the current on such an apex may be called an apex current, and the corresponding applied potential may be called an apex potential.
PAC, 1985, 57, 1491. 'Recommended terms, symbols, and definitions for electroanalytical chemistry (Recommendations 1985)' on page 1494 (https://doi.org/10.1351/pac198557101491)