How to fit Gaussian/Lorentzian lines

 Example :  Spectrum showing overlapping gaussian/lorentzian lines  

Step 1 : Setting up the starting solution (the different lines)

  1. Open the file in dmfit [Menu/File/Open] or drag it to dmfit window from file manager

  2. Initiate a decomposition [Menu/Decomposition/New Fit]

  3. Select a nucleus by Clicking the button or calling the [Spec Parameters] dialog.

  4. Click the [Add] button to add a new line

  5. Click the [Drag] button to drag this new line to a convenient position, widht and amplitude, click left to accept (click right toggles between Amp/Pos and Amp/Width modes).

  6. Check or modify the lines parameters in the [Fit Pannel] (bottom of screen)

  7. Press the [Compute] button to recompute the model spectrum

  8. Repeat this procedure for all the lines that you expect.

Line Parameters (Bold parameters are selected for automatic optimization):
Amplitude : height of the maximum of the line
    Position : Position of the line (in Hertz, ppm or point depending on the current unit)
    Width : full width at half maximum of the line
    xG/(1-x)L : Gaussian/Lorentzian ratio (1 for Gaussian, 0 for Lorentzian)

You can always click use the Fit Parameters Pannel buttons

Step 2 : Optimizing the fit

  1. Check the different lines and their parameters (only Bold face parameters will be optimized)

  2. If necessary click the [Parameters] button to call the [Model Parameters full list] dialog and modify the list of variable paramters

  3. Click the [Optimize] button to optimize the current solution

Step 3 : Reporting and Saving

Fit parameters can be saved in machine readable binary format [Menu/Decomposition/Save Fit] or [Menu/Decomposition/Save as Fit] and thus retrieved later exactly in same state.

Parameters can be reported in human readable format by clicking the [Report] button to report the current line paramters in a dialog box from which you can Select/Copy and further Paste word processing or SpreadSheet programs.