The spectrumfitter package is an obect-oriented framework for fitting dielectric spectra.

The following lineshapes are supported (bold text refers to the class name):

• Debye - Debye dielectric relxation
• DHO - Damped harmonic oscillator
• Gaussian() - Gaussian function for imaginary part and corresponding real part.
• Constant() - constant function for real part, 0 imaginary part.
• ColeCole() - Cole-Cole dielectric relaxation
• VanVleck() - Van Vleck & Weisskopf lineshape [Rev. Mod. Phys., 17:227 236, (1945)]
• BrendelDHO - Brendel DHO [Ref: J. Appl. Phys. 71, 1 (1992) ]
• PowerLawDebye() - Debye lineshape with truncated power law wing. [J. Phys. Chem. B 109 (12), 6031 (2005)]
• StrExp - Stretched exponential relaxation lineshape (a non-analytic function).

Besides basic fitting it has several advanced features, such as:

• Use the f-sum rule as a constraint
• Use the generalized LST (gLST) relation as a constraint
• Fit and plot the longitudinal dielectric function

Example codes are shown in the examples directory.