Open AccessX‐ray natural circular dichroism in langasite crystal
Author(s) -
Oreshko Alexey P.,
Ovchinnikova Ele.,
Rogalev Andrei,
Wilhelm Fabrice,
Mill Boris V.,
Dmitrienko Vladimir E.
Publication year - 2018
Publication title -
journal of synchrotron radiation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.172
H-Index - 99
ISSN - 1600-5775
DOI - 10.1107/s1600577517015387
Subject(s) - quadrupole , crystal (programming language) , perpendicular , dipole , molecular physics , chemistry , crystallography , materials science , optics , physics , atomic physics , geometry , mathematics , organic chemistry , computer science , programming language
Optical activity in the X‐ray range stems from the electric‐dipole–electric‐quadrupole interference terms mixing multipoles of opposite parity, and can be observed exclusively in systems with broken inversion symmetry. The gyration tensor formalism is used to describe the X‐ray optical activity in langasite La 3 Ga 5 SiO 14 crystal with the P 321 space group. An experimental study of the X‐ray natural circular dichroism (XNCD) near the Ga K ‐edge in La 3 Ga 5 SiO 14 single crystal was performed at ESRF beamline ID12, both along and perpendicular to the crystal optical axis. The combination of the quantum mechanical calculations and high‐quality experimental results has allowed us to separate the contributions into X‐ray absorption and XNCD spectra of Ga atoms occupying three distinct Wyckoff positions.