Approximate expressions for X-ray resonant and Mössbauer reflectivity in the total external reflection region are developed for the limiting cases of a semi-infinite mirror with a small resonant addition to the total susceptibility and for the case of an ultrathin resonant layer. It is shown that in this region the reflectivity can depend linearly on the imaginary part of the refraction index; therefore in these cases the consideration of reflectivity spectra (R-spectra) as absorption resonant spectra, taken up in several experimental studies, can be justified. However, several effects producing dispersive distortions of the R-spectrum shape, even for very small grazing angles, have been found. It has been shown that dispersive corrections to the R-spectrum shape are mostly necessary if the non-resonant absorption is relatively large. Model calculations demonstrate that the quantitative spectroscopic information extracted from R-spectra using the software developed for absorption spectra can be inaccurate.

中文翻译：

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反射光谱作为吸收共振光谱：正确吗？

对于在总磁化率中增加少量谐振的半无限反射镜的极限情况和超薄谐振层的情况，开发了外全反射区域中 X 射线谐振和穆斯堡尔反射率的近似表达式。结果表明，在该区域中，反射率可以线性地取决于折射率的虚部；因此，在这些情况下，将反射光谱（R 光谱）视为吸收共振光谱，在一些实验研究中采用是合理的。然而，已经发现了几种产生 R 谱形状色散畸变的效应，即使对于非常小的掠射角也是如此。已经表明，如果非共振吸收相对较大，则最需要对 R 谱形状进行色散校正。