Search results for "absorption spectroscopy"
showing 10 items of 828 documents
Resonant scattering in macromolecular structure research. Applications in molecular biology and material science
1983
Abstract This report concerns the X-ray resonance scattering work carried out using the instrument X15 which receives synchrotron radiation from the storage ring DORIS. X15 covers a wavelength range from 0.6 to 3.3 A. It therefore accesses resonance scattering at the K-absorption edges of the elements with Z = 20 (Ca) to Z = 42 (Mo) and at the L 3 -absorption edges from Z = 50 (Sn) to all heavier atoms. The instrument consists of a double monochromator with a vertical offset of the beam by 1.22 m and a camera of 10 m length. A multiwire proportional chamber (from A. Gabriel) at the end of the evacuated beam line detects the scattered X-ray photons on its area 200 mm × 200 mm. The distances …
Total absorption spectroscopy study of the β decay of Br86 and Rb91
2017
The beta decays of 86Br and 91Rb have been studied using the total absorption spectroscopy technique. The radioactive nuclei were produced at the IGISOL facility in Jyvaskyla and further purified using the JYFLTRAP. 86Br and 91Rb are considered high priority contributors to the decay heat in reactors. In addition 91Rb was used as a normalization point in direct measurements of mean gamma energies released in the beta decay of fission products by Rudstam et al. assuming that this decay was well known from high-resolution measurements. Our results shows that both decays were suffering from the Pandemonium effect and that the results of Rudstam et al. should be renormalized.
A Method to Measure the Characteristics of Biological Materials at Millimeter Waves
1976
A new method of biological sample characterization at millimeter waves has been studied to verify and extend Webb's experimental results. This method, based on interferometric measurements, is suitable to obtain an absorption spectrum of a living bacterial sediment with a high sensitivity. It has been applied in the frequency range 66-73 GHz. Some experimental results are reported.
A search for diffuse absorption bands in carbon-rich stars -- I. Barium and related stars
2003
The results of a search for interstellar and circumstellar absorption lines in high-resolution optical spectra of seven late-type stars are presented. All these stars are single-lined spectroscopic binaries with unseen companions, presumably white dwarfs. Some residual material indicative of recent mass transfer from an asymptotic giant branch (AGB) star might still be associated with the systems. Peculiar energy distribution and the sodium D 1 and D 2 lines give direct evidence about the material in the line of sight in some cases. Absorption features of simple carbon-bearing molecules (C 2 , CN) have been detected in most of the examined stars, confirming a carbon-rich nature of the corre…
Spectroscopy of Hexafluorides with an Odd Number of Electrons: The Vibronic Bands of IrF6
1996
Abstract The low resolution absorption spectroscopy of the first five excited electronic states of IrF 6 has made possible some new assignments for the vibronic transitions of this molecule, and the determination of new vibronic parameter values. They are more accurate than those found in the literature. In this aim, we introduce a simplified tensorial formulation for the linear Jahn–Teller terms in a fourfold degenerate electronic state of an XY 6 -type molecule, which allows easier computation of matrix elements and avoids the use of perturbation theory. Methods for IrF 6 synthesis (using a dynamical flow system) and purification are also presented.
Radiation defects and transition ions interaction in magnesium oxide
2007
Abstract The absorption spectra of nickel and manganese doped and pure MgO single crystals were investigated before and after fast neutron irradiation and after annealing. It is shown that the fast neutron irradiation leads to the formation of two types complex center: “Me 2+ –F + (or F) center” and “Me 3+ –V Mg ”. From the behavior of the ∼570 and ∼357 nm absorption bands during annealing the activation energies of the corresponding defects are determined. The obtained activation energy values ( E a
Hard X-ray resonant electronic spectroscopy in transition metal oxides
2005
K-edge X-ray absorption and 2p-XPS spectra of 3d-element oxides present spectral features which cannot be explained within a simple one-electron model. These features reveal the fine electronic structure of transition metal (TM) oxides valence states resulting from hybridized TM-3d and O-2p states, and the correlations between these valence electrons. In this paper, we show how resonant electronic spectroscopy (resonant Auger or resonant photoelectron spectroscopy) around the TM K-edge can be used to interpret the structures of the threshold and, with the help of theoretical calculation, to determine the electronic configuration of the excited ion. Quadrupolar transitions towards localized …
Total absorption spectroscopy of 58Cu decay
2001
The β decay of 58Cu has been studied by means of total absorption γ-ray spectroscopy. The β feeding to the 58Ni states has been measured, and the strength of the 58Cu(1+) →58Ni(0+) Gamow-Teller transition has been determined with improved accuracy.
EXAFS study of mixed nickel molybdenum oxide thin films at the Ni and Mo K-edges
2004
Mixed nickel molybdenum oxide thin films were produced by DC magnetron co-sputtering technique with the nickel content about 8, 16 and 25 at%. X-ray absorption spectroscopy at the Ni and Mo K-edges was used to study the local atomic structure in the films. The best-fit analysis of the EXAFS signals suggests that (i) the films are amorphous, except for the highest nickel content (25 at%), at which a segregation of NiO phase was observed; (ii) nickel and molybdenum atoms are octahedrally coordinated by oxygen atoms. Opposite to the NiO6 octahedra, the MoO6 octahedra are strongly distorted, that results in an existence of two groups of oxygen atoms—four nearest at B1.76 ( A and two distant at …
Beta decay studies with total absorption spectroscopy and the Lucrecia spectrometer at ISOLDE
2017
26 pags., 21 figs., tab. -- Open Access funded by Creative Commons Atribution Licence 3.0