A simple formula for the thickness correction of symmetrical mössbauer doublets. Application to spin cross-over systems

We have calculated the Mossbauer absorption integral for symmetrical quadrupole doublets as a function of the effective thicknessT of the sample and of the ratioQS/⇏ (quadrupole splitting/natural width); the resulting absorptionA can be well approximated by a simple expressionA≈T/(1+αT), where α is a function of the resolutionQS/⇏ of the absorption lines. A convenient analytical expression is given for α(QS/⇏). As an example, the thermal variation of the absorption area of a spin crossover system is analysed.