What it does

One environment for the whole Mössbauer analysis.

Discrete fitting, hyperfine-field distributions and well-characterised uncertainties, behind a clear, reproducible interface.

Discrete fit

Singlets, doublets & sextets

Up to three components, Lorentzian/Voigt profiles, Poisson or Gaussian likelihood, robust losses and χ²/AIC/BIC statistics.

Distributions

P(BHF), P(ΔEQ), P(IS) & 2D

Tikhonov / total-variation / maximum-entropy regularization, L-curve α estimation and simultaneous sharp components.

Uncertainties

Errors you can trust

Multi-start optimisation, Monte Carlo bootstrap errors and profile-likelihood confidence intervals.

Advanced physics

Kündig, texture & relaxation

Kündig quadrupole treatment, intensity texture, physical-constraint presets and relaxation models (Blume–Tjon, Néel–Arrhenius).

Productivity

Batch, CLI & reports

Batch fitting with warm-start, a headless CLI, Markdown/PDF reports, full JSON sessions and a semi-manual minimum editor.

Open

Free, trilingual, reproducible

Open source (Apache 2.0), interface and help in Spanish, English and French, plus built-in update checking.

0.38

isomer shift (mm/s)

ΔEQ

−0.11

quadrupole split (mm/s)

B_HF

49.2

hyperfine field (T)

0.29

linewidth (mm/s)

100%

relative area

χ²ᵣ

1.02

goodness of fit

Get started in five minutes.

Download it for free and try the bundled sample spectra (magnetite, hematite, metallic iron…).

git clone https://github.com/sullymike/Fitbauer.git && python fitbauer.py

Downloads / Releases → GitHub

Citation

How to cite Fitbauer

If Fitbauer has been useful in your work, please cite the software through its DOI. The concept DOI always resolves to the latest published version.

Recommended citation

Bibliographic format

Sánchez-Marcos, J., & Menéndez, N. (2026). Fitbauer (v5.1.0) [Software]. Universidad Autónoma de Madrid. Zenodo. https://doi.org/10.5281/zenodo.21858360

Replace the version number with the one you actually used; the concept DOI does not change.

BibTeX

Entry for reference managers

@software{fitbauer,
  author    = {S{\'a}nchez-Marcos, Jorge and Men{\'e}ndez, Nieves},
  title     = {Fitbauer: open-source software for
               M{\"o}ssbauer spectrum fitting and analysis},
  year      = {2026},
  version   = {5.1.0},
  publisher = {Zenodo},
  doi       = {10.5281/zenodo.21858360},
  url       = {https://doi.org/10.5281/zenodo.21858360},
  license   = {Apache-2.0}
}

The repository ships a CITATION.cff file that GitHub and Zotero read automatically.

Persistent identifiers

DOI (Zenodo)

Concept DOI 10.5281/zenodo.21858360
v5.1.0 DOI 10.5281/zenodo.21858361
Source code github.com/sullymike/Fitbauer
Licence Apache-2.0

Use the concept DOI unless you need to refer to a specific version for reproducibility.

Software Heritage

SWHID (source code archive)

Identifier of the code archived in Software Heritage, in its fully qualified form.

swh:1:dir:2d69817a33ec310004104ccd90b579760e9384ac;
origin=https://github.com/sullymike/Fitbauer;
visit=swh:1:snp:394a5f0175a81606bd4eab5ec39dedf3ef1ed741;
anchor=swh:1:rev:8a527b6dc1b5ecebce0b898606db84f71dba5c34

The swh:1:dir: part identifies one specific source tree and changes with every archived commit; the swh:1:snp: snapshot identifies the repository and is more stable.