The program has a menu, speed buttons and four tabs.
|creates a default data template|
|loads selected data file|
|writes current data (including fitting results) into a file|
|prints a hard copy of the data|
|prints the fitting curves|
|checks data validity|
|single fitting iteration|
|multiple iterations *)|
*) Multiple iterations - uses values from the Results Tab: Stops if number of iterations exceeds IterMax, the mean square deviation becomes less then dPPM, or energy step becomes smaller than dEmin
This bar also contains the One-level Fit checkbox - Curie fit if checked, Two-level fit if unchecked.
This tab contains the program title and contact information.
The experimental data can be loaded from a file or entered manually.
To load data go to "File", "Open" and select a file. The standard extension is *.tdf. Actually the TDF-files are plain text files and can be created or modified using any text processor. The file structure is described below. The contents of the input file are displayed in the "Input" tab.
The "Input" tab can be also used for manual input.
NExperim - NParam: Data Redundancy is determined automatically in calculations (Must be > 0).
Sometimes it is necessary to remove the entire row or column in the data grid (usually due to the low accuracy of measurement). This can be done by Shift-clicking (rows) or Ctrl-clicking (columns). The excluded rows and columns are marked as "X":
The values are not actually deleted, they are just not used in the fitting procedure. They can be undeleted by Shift/Ctrl clicking again. In the above example the 3rd point and the line "b" are excluded. In the output file (see the section below) the deleted values are labeled with zero weights:
Weight factors: Line 1 Line 2 Line 3 Line 4 Point 1 1 0 1 1 Point 2 1 0 1 1 Point 3 1 0 1 1 Point 4 0 0 0 0 Point 5 1 0 1 1
After loading data from a file or manually entering data it is recommended to check data validity by pressing
For the calculation of initial quantities press
After the initial calculation, the Fitting and Results tabs become available for editing.
After that the fitting can be performed in three ways:
In the above example the energy step is (555.5 - 0.001)/100 = 5.55499 cm-1.
(FAxial + FRhomb) TRef /T
Recalculate: Calculations with new dipolar shifts.
The input file is a simple Text (ASCII) file. Each line contains data and an optional comment string in the end (displayed in red). The same format is used for output files. Below is a sample file.
2 1 1 = Calculated, 0 = Not calculated Curie Dependence Sample File 4 - Number of Lines 5 - Number of Temperature points 0.5 0.5 a | b | c | d -496.8000 -496.8000 -496.8000 -496.8000 - Spin Factors 0.0000 0.0000 0.0000 0.0000 - Dia Shifts 3.4000 -30.0000 -26.6000 -24.8000 -27.7000 - 1000/T, Para Shifts, Point 1 3.5700 -31.4000 -28.0000 -25.8000 -29.3000 - 1000/T, Para Shifts, Point 2 3.9200 -35.4000 -31.1000 -28.1000 -32.9000 - 1000/T, Para Shifts, Point 3 4.3300 -39.6000 -34.1000 -30.0000 -36.7000 - 1000/T, Para Shifts, Point 4 4.8200 -44.6000 -37.6000 -32.2000 -41.3000 - 1000/T, Para Shifts, Point 5
Remark 1: All comments (displayed in red) are optional and can be omitted.
Remark 2: All values should be separated by at least one space.
The output files contains the input information in the beginning (this means that output files can be used as input files also).
Next, the output file contains the data from the Results tab.
After that, the fitting curves are recorded (1000/T, Paramagnetic Shifts - 51 equidistant points). They can be used in plotting programs.
The weight matrix is recorded at the end of output files.
The weight matrix is 1 if the point was used in fitting or 0 if it was excluded.
Weight factors: Line 1 Line 2 Line 3 Line 4 Point 1 1 1 0 1 Point 2 1 1 0 1 Point 3 1 1 1 1 Point 4 1 1 1 1 Point 5 1 1 1 1
In the above example the first two points of the third line were excluded (or are missing).
Back to Temperature Dependence of NMR
©Nikolai V. Shokhirev, 2002-2004