Open AccessDevelopment of light‐modulated XAFS spectroscopy
Author(s) -
Okamoto Kaoru,
Kohdate Kenji,
Nagai Kensuke,
Miyawaki Jun,
Kondoh Hiroshi,
Yokoyama Toshihiko,
Nojima Akihiro,
Ohta Toshiaki
Publication year - 2003
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/s0909049503004321
Subject(s) - x ray absorption fine structure , monochromator , spectroscopy , excited state , chopper , xanes , materials science , extended x ray absorption fine structure , chemistry , absorbance , optics , absorption spectroscopy , analytical chemistry (journal) , optoelectronics , atomic physics , physics , wavelength , quantum mechanics , voltage , chromatography
The light‐modulation method was applied to XAFS spectroscopy as a useful tool for electronic and structural studies of light‐excited states. The visible light for electronic excitation was modulated by an optical chopper and the concomitant change in the X‐ray absorbance was extracted by a lock‐in amplifier. It is essential to reduce any noise arising from several sources, especially those generated by the X‐ray monochromator. Fe and Co K ‐edge XANES and EXAFS spectra were measured using the present approach for spin transition compounds. The light‐modulated XAFS method is found to be applicable to systems with an excited‐state ratio of less than several percent. Detailed discussion is also given concerning quantitative measurements, including the signal amplitude and phase shift information.