Open AccessHigh‐resolution X‐ray spectroscopy of rare events: a different look at local structure and chemistry
Author(s) -
Bergmann Uwe,
Glatzel Pieter,
Robblee John H.,
Messinger Johannes,
Fernandez Carmen,
Cinco Roehl,
Visser Henk,
McFarlane Karen,
Bellacchio Emanuele,
Pizarro Shelly,
Sauer Kenneth,
Yachandra Vittal K.,
Klein Melvin P.,
Cox Billie L.,
Nealson Kenneth H.,
Cramer Stephen P.
Publication year - 2001
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/s0909049500016484
Subject(s) - x ray absorption fine structure , chemistry , extended x ray absorption fine structure , xanes , absorption (acoustics) , raman spectroscopy , synchrotron radiation , valence (chemistry) , x ray raman scattering , absorption spectroscopy , spectroscopy , fluorescence , scattering , analytical chemistry (journal) , raman scattering , physics , optics , quantum mechanics , organic chemistry , chromatography
The combination of large‐acceptance high‐resolution X‐ray optics with bright synchrotron sources permits quantitative analysis of rare events such as X‐ray fluorescence from very dilute systems, weak fluorescence transitions or X‐ray Raman scattering. Transition‐metal K β fluorescence contains information about spin and oxidation state; examples of the characterization of the Mn oxidation states in the oxygen‐evolving complex of photosystem II and Mn‐consuming spores from the marine bacillus SG‐1 are presented. Weaker features of the K β spectrum resulting from valence‐level and `interatomic' ligand to metal transitions contain detailed information on the ligand‐atom type, distance and orientation. Applications of this spectral region to characterize the local structure of model compounds are presented. X‐ray Raman scattering (XRS) is an extremely rare event, but also represents a unique technique to obtain bulk‐sensitive low‐energy (<600 eV) X‐ray absorption fine structure (XAFS) spectra using hard (∼10 keV) X‐rays. A photon is inelastically scattered, losing part of its energy to promote an electron into an unoccupied level. In many cases, the cross section is proportional to that of the corresponding absorption process yielding the same X‐ray absorption near‐edge structure (XANES) and extended X‐ray absorption fine structure (EXAFS) features. XRS finds application for systems that defy XAFS analysis at low energies, e.g. liquids or highly concentrated complex systems, reactive compounds and samples under extreme conditions (pressure, temperature). Recent results are discussed.