Collect. Czech. Chem. Commun. 1991, 56, 20-41

Accuracy contours in (nT, λ) space in electrochemical digital simulations

Dieter Britza and Merete F. Nielsenb

a Kemisk Institut, Aarhus Universitet, 8000 Aarhus C, Denmark
b Department of General and Organic Chemistry, The H.C. Ørsted Institute, Universitetsparken 5, 2100 Copenhagen, Denmark


In finite difference simulations of electrochemical transport problems, it is usually tacitly assumed that λ, the stability factor Dδtx2, should be set as high as possible. Here, accuracy contours are shown in (nT, λ) space, where nT is he number of finite difference steps per unit (dimensionless) time. Examples are the Cottrell experiment, simple chronopotentiometry and linear sweep voltammetry (LSV) on a reversible system. The simulation techniques examined include the standard explicit (point- and box-) methods as well as Runge-Kutta, Crank-Nicolson, hopscotch and Saul’yev. For the box method, the two-point current approximation appears to be the most appropriate. A rational algorithm for boundary concentrations with explicit LSV simulations is discussed. In general, the practice of choosing as high a λ value when using the explicit techniques, is confirmed; there are practical limits in all cases.