Polarisation effects in Mössbauer absorption by powder samples in external magnetic fields

The polarisation dependence of the absorption cross section must generally be taken into account in calculating Mössbauer absorption spectra of powder samples if they are partly polarised by an external magnetic field. The dependence of the intensity of the absorption lines on the aboorber thickness with an external field ofH _a=50 kG is shown in the case of the paramagnetic specimen Fe(ClO₄)₂·6H₂O. The calculation procedure is described and the results are compared with the usual thickness corrections neglecting polarisation effects.