q-Gaussian and q-BWF functions for the deconvolution of Raman and infrared spectra of Calcite

Here we consider calcite and its spectra (Raman and infrared) that we can find in the RRUFF database. We apply q-Gaussian and q-BWF functions to decompose the spectra. The q-Gaussian functions had been derived in the framework of Tsallis analysis of entropy. Their use for Raman spectroscopy has been proposed by Sparavigna, 2023. The q-BWF functions have been defined by Sparavigna, 2023, to generalize the BWF (Breit-Wigner-Fano) functions, and proposed for fitting to asymmetric peaks in Raman spectroscopy. Besides examples of decompositions of RRUFF spectra, a review of literature about calcite is given. We will also add an appendix about the Raman spectra of calcite recorded by R. S. Krishnan (1945), by means of the F. Rasetti technique (1932) which was using the λ2536.5 mercury resonance radiation. As we can see, Krishnan succeeded to record the second order components of the spectrum.