Institut für Anorganische und Analytische Chemie, Johannes Gutenberg Universität Mainz, Staudinger
Weg 9, D–55099 Mainz, Germany
As scientists examine more and more complex phenomena and systems, are taking into account more
details, they are more frequently faced with the necessity of simultaneous evaluation of raw data of
measurements performed on the same sample with different methods and/or with the same method at
different temperature, pressure, magnetic field, etc. This need is justified by the fact that such experimental
data partly depend on the same set of parameters, viz. the physical parameters of the sample, i.e., the
parameters the experimentalist is typically interested in. Lacking suitable programs for the simultaneous
evaluation of all these data, the experimentalist is often forced to evaluate some of the parameters from
only one kind of measurements and to keep these parameters constant when evaluating other experiments,
an obviously incorrect approach. Besides, for different theories different programs are used, which makes
very difficult tuning parameters of such theories to each other and to extend or modify the theories used for
describing different experimental data.
Over the past years, we have developed the general and versatile data fitting environment EFFI
(Environment For FItting) [1], which has been very efficiently applied for the evaluation of many sets of
‘conventional’ transmission and ‘synchrotron’ Mössbauer spectra the latter including grazing-incidence,
i.e., synchrotron Mössbauer reflectometry (SMR) [2] measurements, both time-differential and time-
integral. Presently, EFFI is capable of simultaneously fitting several data sets of the following kinds of
experiments:
o Conventional Mössbauer absorption and emission spectroscopy
o X-ray reflectometry
o Nuclear resonant forward scattering of synchrotron radiation: time differential mode
o Nuclear resonant forward scattering of synchrotron radiation: stroboscopic mode
o Synchrotron Mössbauer reflectometry: time integral, time differential and stroboscopic modes
o Specular polarized neutron reflectometry
o Off-specular polarized neutron reflectometry
Beside the enumerated spectroscopies, a programmer interface is provided to include new theories. The
versatility of EFFI is ensured by handling constraints in terms of general and editable correlation matrices
linking parameters of different theories and thereby defining the real physical parameters.
The
main and yet essential disadvantage of the old versions of EFFI was the fact that its user interface
was written using development tools available in the eighties and, therefore, in spite of its scientific merits,
its user-friendliness was considerably limited.
We are presenting the test version of a new generation of EFFI. This environment, based on a user
interface written in C++, is a widely available, free, thoroughly documented program. Extended capabilities
of EFFI include an up-to-date and user-friendly graphical user interface, which may be developed further as
an international project of several groups active in the field and to complement its present capabilities by
theories of new experimental methods, including off-specular neutron reflectometry, off-specular
synchrotron Mössbauer reflectometry, i.e., methods, which are being increasingly used in the field of
magnetic thin film research.
This work was supported by the European Community under the Specific Targeted Research Project
Contract No. NMP4-CT-2003-001516 (DYNASYNC). The new generation of EFFI is being developed in
frames of DYNASYNC and the final version will be freely available and downloadable from the project
website DYNASYNC with the only provision of properly acknowledging its usage in upcoming publications.
[1] H. Spiering, L. Deák, L. Bottyán, Hyperfine Interact. 125 (2000) 197.
[2]
D.L. Nagy, L. Bottyán, L. Deák, E. Szilágyi, H. Spiering, J. Dekoster, G. Langouche, Hyperfine
Interact. 126 (2000) 353.