2D-correlation analysis applied to in situ and operando Mossbauer spectroscopy

摘要

In this paper we propose a new way for Mossbauer data treatment when numerous experimental spectra are recorded in operando conditions depending on a perturbation. In our example, the perturbation is the Li amount extracted from a positive electrode material LiFe_(0.75)Mn_(0.25)PO_4. In other cases perturbation could be the recording temperature, the pressure or kinetic parameter or even time for isothermal experiments. From analysis of both synchronous and asynchronous 2D-correlation spectra, we can focus our attention on the intensity variations at some specific positions deduced from cross-peaks. This analytical method is very powerful when overlap between absorption lines is observed. This is typically the case when Fe~(2+)/Fe~(3+) contributions are simultaneously present in a Mossbauer spectrum at lower velocities.