Decomposition of two overlapping bands

Consider the MIR spectrum of carbon tetrachloride (M1R TETRA) that exhibits a spectral feature of two overlapping bands at about 780 cm . Choose the suitable spectral range, check Save Single Peaks Too, start the interactive mode and enter two curves initially. Then the curve fit set-up window could look like that shown in Fig. 11.3. For better initial parameter values add a baseline and alter the shape of both curves to a fifty fifty mixture of Lorentzian and Gaussian functions. Follow the same steps as mentioned above and you will find that the fitting procedure converges after a very short time. The result is shown in Fig. 11.4. By clicking on the button Save Peaks and Reps you can save the fit report and every fitted peak will be stored as a separate file named FIT. 

The fit report is given in Fig. 11.5. Of course all fitted bands can be also represented as spectra, as illustrated in Fig. 11.6. In this way it is possible to visually compare the original spectrum with the theoretical spectrum consisting of all constituent bands and the baseline. 

C OPUSDEMO DATA MIR TETRA.O Number of peaks Algorithm Levenberg-Marquardt Max. Iteration time x-Start x-End Residual RMS error 3.000000 10.000000 900.000000 650.000000 0.003759  

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