fityk - free peak fitting softwareFityk [fi:tik] is for peak fitting. Longer version: fityk is a program for nonlinear fitting of analytical functions (especially peak-shaped) to data (usually experimental data). There are also people using it to remove the baseline from data, or to display data only. It is reportedly used in crystallography, chromatography, photoluminescence and photoelectron spectroscopy, infrared and Raman
https://kosmosfs.sourceforge.net/
http://langrid.nict.go.jp/download/jp/indexj.html
