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arXiv · 1511.05354

Resonant X-ray Emission Spectroscopy With a Standing Wave Excitation

Kari O. Ruotsalainen·Ari-Pekka Honkanen·Stephen P. Collins·Giulio Monaco·Marco Moretti Sala·Michael Krisch·Keijo Hämäläinen·Mikko Hakala·Simo Huotari
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Abstract

The Borrmann effect is the anomalous transmission of x rays in perfect crystals under diffraction conditions. It arises from the interference of the incident and diffracted waves, which creates a standing wave with nodes at strongly absorbing atoms. Dipolar absorption of x rays is thus diminished, which makes the crystal nearly transparent for certain x-ray wave vectors. Indeed, a relative enhancement of electric quadrupole absorption via the Borrmann effect has been demonstrated recently. Here we show that the Borrmann effect has a significantly larger impact on resonant x-ray emission than is observable in x-ray absorption. Emission from a dipole forbidden intermediate state may even dominate the corresponding x-ray spectra. Our work extends the domain of x-ray standing wave methods to resonant x-ray emission spectroscopy and provides means for novel spectroscopic experiments in d- and f-electron systems.

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Kari O. Ruotsalainen, Ari-Pekka Honkanen, Stephen P. Collins, Giulio Monaco, Marco Moretti Sala, Michael Krisch, Keijo Hämäläinen, Mikko Hakala, Simo Huotari. 2017-01-13. Resonant X-ray Emission Spectroscopy With a Standing Wave Excitation. https://doi.org/10.1038/srep22648

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