Add second derivative of data and fit

[Niklas123Niklas]

Hi there, this is a suggestion: I fit IF-Spectra with your program, which is amazing for fitting bands! In IR-spectroscopy, the second derivative of the data contains lots of information, also for fitting and verifing the fit. Is it possible to add a plot of or switch the plot to the second derivative of the spectra and the fit? Cheers, Niklas