Decompose spectra with multiple components

Absorption or emission spectra consisting of multiple absorbing or emitting species

For a mixture of multiple absorbing or emitting components the combined spectrum, B, is the linear combination of the individual component spectra:

    B = x1A1 + x2A2 + ...

If the isolated component spectra, A1, A2, etc., are known then a|e can be used to determine the factors, x1x2, by solving the simple system of linear equations: Ax = B

a|e will fit the spectrum independent of the measured wavelength grids of the individual spectral components.


Decompose spectra consisting of multiple individual spectral components using a|e

In this example, an emission spectrum is fitted to a sum of three individual Gaussian components. Each Gaussian component was created using the Fit spectral band to Gaussian - tool and set to equal heights for illustrative purposes only.



1. Go to Tools -> Spectral decomposition -> Decompose using ref. spectra



2. In the dialog box, select all the spectra to be fit in the left box and the individual component spectra in the right box. a|e will fit each of the chosen spectra in the left box using the component spectra chosen in the right box.



3. Press OK. The component factors, x1, x2, etc., are displayed in the message board. Each fitted spectrum is called 'Fit: "Name of spectrum"' and is added as a new dataset to the data listbox. In the shown screenshot, the fit is highlighted in thick, full-drawn and black.