The application of synchrotron radiation and in particular X-ray absorption spectroscopy to matrix isolated species

Abstract

This review provides comprehensive coverage of the application of X-ray absorption spectroscopy (XAS, XAFS, EXAFS, XANES) to matrix isolated species. As X-ray absorption spectroscopy provides structural data without the need for long range order it has been applied to a large number of systems to yield unique structural data about both the matrix isolated species, and their interactions with the matrix host. To put the work into perspective there is a tutorial introduction to the theoretical background of X-ray absorption spectroscopy, data content, processing and analysis. In addition there is brief coverage of the use of other synchrotron radiation techniques for the study of matrix isolated species, and a consideration of future perspectives.

How Inert, Perturbing, or Interacting Are Cryogenic Matrices? A Combined Spectroscopic (Infrared, Electronic, and X-ray Absorption) and DFT Investigation of Matrix-Isolated Iron, Cobalt, Nickel, and Zinc Dibromides

“…Therefore, relatively weak 1s → 3d peaks are expected for octahedral, square-planar, and linear geometries, with greater intensity expected for trigonalbipyramidal, square-pyramidal, and tetrahedral geometries as well as nonlinear triatomics. 57,112 A second pre-edge feature (peak or shoulder) about 1−3 eV below the edge that is found in the spectra of tetragonal complexes missing one or more axial ligands and in linear complexes has been assigned to 1s → 4p z transitions with shakedown contributions, 112 and this is confirmed by our calculations shown in Figures 1 and 2. Therefore, a sharp intense feature on the edge of the metal K-edge XANES spectrum can be used diagnostically to indicate linearity, and a reduction in the intensity of this feature and the appearance of weak pre-edge features are indicators of the onset of nonlinearity.…”

“…The application of X-ray absorption spectroscopy to matrix-isolated species has recently been reviewed. 57 Gerry carried out extensive microwave studies of the gas-phase complexes between group 11 halides and noble gases (see ref 58 and references therein), and the complexes with xenon as a ligand are also important examples. 59−62 Therefore, there is considerable evidence that the noble gases, while providing an excellent medium for trapping reactive and unstable species, may actually exert a benign and often poorly characterized effect on the trapped species.…”

Bonding Structures of ZrHx Thin Films by X-ray Spectroscopy

“…20,21 XANES provides quantitative information about the average oxidation state of the absorbing element, the local coordination environment, and the unoccupied electronic structure, while EXAFS provides quantitative information about average bond length, the coordination numbers, and type of neighbors as well as the mean-square disorder of the nearest neighboring atoms. 22,23 The XANES and EXAFS investigations are thus complemented with XRD, to assess both the short-and longrange order structural properties of the films.…”

Study of the thermochromic phase transition in CuMo$_{1-x}$W$_x$O$_4$ solid solutions at the W L$_3$-edge by resonant X-ray emission spectroscopy

“…Conventionally, X-ray absorption spectroscopy (XAS) is used to probe the local environment of atoms in complex materials [14,15,16]. However, in the case of tungstates and molybdates, often composed from strongly distorted polyhedra, the recovery of structural information from XAS requires the use of a computationally heavy and time-consuming approach based on reverse Monte Carlo (RMC) simulations [17,18,19,20].…”