DigiElch8 Help

The Property Page: Chemical Reactions works as previously described for the CV-Simulation Document.

The Property Page: Surface Reactions works as previously described for the CV-Simulation Document.

A value of Cdl (F) written in magenta indicates that a time/potential dependent double layer capacity has been entered by the user. The polynomial coefficients describing the dependence of the double layer capacity as function of the electrode potential can be edited by clicking with the right mouse button while the cursor is localized over the input field associated with Cdl (F).

The following parameter groups
 

•Geometry

•Diffusion

•Pre-Equilibrium

•Simulation Name

 
as  well as the Simulation Parameters headlined
 

•Experimental Conditions

•Model Parameters

•2D-Simulation

•FEM-Simulation

work exactly in the same way as already described for cyclic voltammetry. The meaning and functionality of the other parameters is as follows:
 

1. DC - Signal

•Check Box: Single Scan
Activate this check box if only the forward scan of the DC-signal needs to be simulated. Eend (V) is automatically set equal to Erev(V) and the input field for Eend (V) will be blocked.
 

•Estart (V), Erev (V), Eend (V), v(s)
The DC-scan can be composed of up to 2 scan segments characterized by starting potential, Estart (V), reversing-potential, Erev (V), end-potential, Eend (V), and scan rate, v (V/s).

2. Scan Parameters

•log2(Data Points)
The number of data points used for generating the signal. It must be an integer power of 2 and is 2^14 = 16384 by default.

•dEdc (V)
The potential difference between subsequent data points (fitting the selected number of Data Points) is shown in the (read only) parameter dEdc(V).
 

3. AC - Signal

•dEac (V), f(Hz), Phase Angle
The superimposed AC-signal is characterized by Amplitude, dEac (V), frequency, f(Hz), and Phase Angle. The frequency is adjusted such as to ensure an integer value for the number of AC-Cycles.
 
Ideally the sum of the AC and DC signal should converge to Estart (V) at t => 0. Consequently, the ideal AC-signal should be a sinus with a Phase Angle of 0. Unfortunately, when conducting FT-CV-Experiments from within DigiElch (having a GAMRY potentiostat connected) it is not possible to synchronize the DC-signal (generated by the potentiostat's DAC-converter) with the AC-signal (generated by the potentiostat's signal-processor). For this reason the Phase Angle actually used in an experiment will randomly vary from experiment to experiment. This is why DigiElch provides the option to enter the phase angle to which a FT-CV-simulation refers (with respect to an ideal sinus signal).
 

•AC-Cycles
The integer number of AC-Cycles which is superimposed to the DC-signal.