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, A_1, A₂, etc., are known then a|e can be used to determine the factors, x₁, x₂, 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.