Full use-format

the full use-format contains the current curve and a full description of the experimental parameters. The latter must be written to the file in exactly the same form as on the Property Page: Simulation Parameters:
 

DigiElch_CV_Header

experimental parameters:

key_word_1: Value_1

key_word_2: Value_2

.

.
species parameters:

[name of species_1] (M/l): Canal_1

[name of species_2] (M/l): Canal_2

.

.

experimental CV-data:
number of E(V), I (A) couples: N

E_1 , I_1

E_2 , I_2

.

.

E_N , I_N
 

•DigiElch_CV_Header:
source program: DigiElch for Windows
program version: 3.0
file type: CV

•key_word_i and Value_i
key word and value referring to the i-th parameter. The value must be in point-format and separated from the key word by a colon. The keywords and parameter values are identical to those shown on the Property Page: Simulation Parameters. For example,
 
Pre-Equilibrium: enabled
Diffusion: Semi-Infinite 1D
Geometry: Planar
Area (cm²): 0.05
Ru (Ohm): 0
Cdl (F): 0
Temp. (K): 298.2
C1 (F/V): 0
C2 (F/V²): 0
C3 (F/V³): 0
C4 (F/V²V²): 0
Potential steps (V): 0.001
Estart (V):-0.75
Segment: 1
Eend (V): -1.55
v (V/s): 100
Segment: 2
Eend (V): -0.75
v (V/s): 100

•name of species_i and Canal_i
the name of the i-th species in brackets and the analytical concentration in point-format. For example
 
[NiL] (M/l): 0.001
[NiL-] (M/l): 0
[DP] (M/l): 0.1
[NiLDP] (M/l): 0
[NiLDP-] (M/l): 0

•N
the number of data couples

•E_i and I_i
numbers representing the i-th Voltage-Current-couple separated by comma

Minimum use-format

Data measured with third-party electrochemical instruments are usually exported in file formats which differ from instrument to instrument. The minimum use-format enables the user to produce an importable use-file with a minimum of effort provided the experimental data files satisfy the following prerequisites:
 

•The experimental current curve is available in ASCII-format.

•The current points refer to equal potential steps. Only small deviations from an equally spaced potential scan do not matter.

The minimum use-format is as follows:
 

DigiElch_CV_Header

experimental CV-data:
number of E(V), I (A) couples: N

E_1 , I_1

E_2 , I_2

.

.

E_N , I_N

•E_i and I_i
numbers representing the i-th Voltage-Current-couple separated by comma

Files in minimum use-format do not contain any information about experimental parameters such as scan rate, electrode surface, electrode geometry or species concentrations. It is therefore not possible for the fitting procedure to recognize to which parameter combination a particular experimental curve refers. Consequently, such files are useful only for viewing experimental current curves. Apply the Edit/Modify command  to add the experimental parameters to each file.

This command opens a dialog box that offers the user to define an import-filter for importing data stored in an ASCII-format which is not compliant with DigiElchs use-file format. After leaving with OK, a standard Windows file dialog appears and the the selected file will be imported using the assignment of data defined in the import filter.

•Selected Import-Filter
By default DigiElch offers predefined import filters for

oGAMRY-CV dta-files

oBAS-CV txt-files

oPAR-CV dat-files

oAutolab-CV ocw-files

oUser Defined

The last one can be freely configured by the user. Use Add New if more than one user defined import filter is required.
 

•ID-String marking begin of Data Section and Data Format
It is assumed that the ASCII-file consists of an header followed of a data section containing the current-voltage data. If the ID-String is not empty, DigiElch ignores all lines imported before reading the ID-String.
 
 
The ID-String might be empty unless the header contains data arranged in columns which can be confused with those containing the current-voltage values.
 

•Data Format
When the ID-String has been reached, the program checks whether the imported line contains data which are compliant with the specified Number of columns and the selected Separator. If yes, another current-voltage couple is added to the experimental CV using the assignment defined in E(V) refers to column and I(A) refers to column. Adjust the scaling factors correspondingly, if the unit of the imported current is not given in Ampere (but μA, for instance) or if the unit of the voltage is not given in Volt.
 
The scaling factor must be greater 0. If you need to change the current convention (DigiElch requires the classical convention where cathodic current is positive) use the Option: Import Data provided on the Properties windows.

•Assign scan segments automatically
The automatic assignment works only if the imported voltage values refer to a smooth scan where the sign of dE/dt changes only at the end of the scan segment. If the file contains an experimentally sampled voltage curve which is noisy it might be necessary to assign the scan segments manually using the following dialog box that appears after importing the file when leaving this check box unticked.

The imported E/I-couples are listed on the left-hand side of the dialog box. Simply check whether the number of scan segments detected by DigiElch is the correct one and whether the individual switching points refer to the correct data points.

Usually data files produced by third-party instruments do not contain any information about experimental parameters such as scan rate, electrode surface, electrode geometry or species concentrations. It is therefore not possible for the fitting procedure to recognize to which parameter combination a particular experimental curve refers. Consequently, such files are useful only for viewing experimental current curves. Apply the Edit/Modify command  to add the experimental parameters to each file.