491 research outputs found
Determining the Electron-Phonon Coupling Strength in Correlated Electron Systems from Resonant Inelastic X-ray Scattering
We show that high resolution Resonant Inelastic X-ray Scattering (RIXS)
provides direct, element-specific and momentum-resolved information on the
electron-phonon (e-p) coupling strength. Our theoretical analysis demonstrates
that the e-p coupling can be extracted from RIXS spectra by determining the
differential phonon scattering cross section. An alternative, very direct
manner to extract the coupling is to use the one and two-phonon loss ratio,
which is governed by the e-p coupling strength and the core-hole life-time.
This allows measurement of the e-p coupling on an absolute energy scale.Comment: 4 pages, 3 figure
Magnetic circular dichroism of x-ray absorption spectroscopy at rare-earth L2,3 edges in RE2Fe14B compounds (RE = La, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu)
Magnetic circular dichroism (MCD) in the x-ray absorption spectroscopy (XAS)
at the L2,3 edges for almost entire series of rare-earth (RE) elements in
RE2Fe14B, is studied experimentally and theoretically. By a quantitative
comparison of the complicated MCD spectral shapes, we find that (i) the 4f-5d
intra-atomic exchange interaction not only induces the spin and orbital
polarization of the 5d states, which is vital for the MCD spectra of the
electric dipole transition from the 2p core states to the empty 5d conduction
band, but also it accompanies a contraction of the radial part of the 5d wave
function depending on its spin and orbital state, which results in the
enhancement of the 2p-5d dipole matrix element, (ii) there are cases where the
spin polarization of the 5d states due to the hybridization with the spin
polarized 3d states of surrounding irons plays important roles, and (iii) the
electric quadrupole transition from the 2p core states to the magnetic vale!
nce 4f states is appreciable at the pre-edge region of the dipole spectrum.
Especially, our results evidence that it is important to include the
enhancement effect of the dipole matrix element in the correct interpretation
of the MCD spectra at the RE L2,3 edges.Comment: 9 pages, 5 figures, 1 table, REVTe
Global effects of EU agenda 2000 : implications for the WTO negotiations and developing countries
Scaling Propensity of Water
The commonly used Saturation Index calculated at 10°C (SI10) is not suitable for practical situations. New parameters have been developed for simple and rapid analysis of calcium carbonate precipitation (scaling) phenomena which occur during the heating of drinking water: TPCC90 (Theoretically Precipitable Calcium Carbonate at 90°C) SI90 (Saturation Index at 90°C) NI (Nucleation Index) PPCC (Practically Precipitable Calcium Carbonate) Both TPCC90 and SI90 describe the hydrodynamic driven force for the scaling reaction. The nucleation index indicates at what rate calcium carbonate precipitation is accelerated by nuclei present in the water. Finally, the PPCC is a measurement under practical conditions, determining the rate of scaling. The suitability of these parameters for predicting scaling was assessed and detailed results are presented in this publication
Comment on ``Spin Polarization and Magnetic Circular Dichroism in Photoemission from the 2p Core Level of Ferromagnetic Ni''
Although the Ni_4 cluster includes more information regarding the Ni band
structure with respect to the Anderson impurity model, it also favors very
peculiar ground states which are incompatible with a coherent picture of all
dichroism experiments.Comment: 1 page, RevTeX, 1 epsf figur
Resonant Inelastic X-Ray Scattering at the K Edge of Ge
We study the resonant inelastic x-ray scattering (RIXS) at the edge of
Ge. We measure RIXS spectra with systematically varying momenta in the final
state. The spectra are a measure of exciting an electron-hole pair. We find a
single peak structure (except the elastic peak) as a function of photon energy,
which is nearly independent of final-state momenta. We analyze the experimental
data by means of the band structure calculation. The calculation reproduces
well the experimental shape, clarifying the implication of the spectral shape.Comment: 17 pages,9 figures, Please also see our related paper:
cond-mat/040500
When the Right (Drug) Should Be Left:Prenatal Drug Exposure and Heterotaxy Syndrome
Background: Recent studies reported an association between prenatal propylthiouracil exposure and birth defects, including abnormal arrangement across the left-right body axis, suggesting an association with heterotaxy syndrome. Methods: This case-control and case-finding study used data from 1981 to 2013 from the EUROCAT birth defect registry in the Northern Netherlands. First, we explored prenatal exposures in heterotaxy syndrome (cases) and Down syndrome (controls). Second, we describe the specific birth defects in offspring of mothers using propylthiouracil (PTU) prenatally. RESULTS: A total of 66 cases with heterotaxy syndrome (incidence 12.1 per 100,000 pregnancies) and 783 controls with Down syndrome (143.3 per 100,000 pregnancies) were studied. No differences in intoxication use during pregnancy were found between cases and controls, including smoking (28.0% vs. 22.7%; p = 0.40), alcohol (14.0% vs. 26.9%; p = 0.052), and recreational drugs (0 vs. 0.3%; p = 1.00). We found an association between heterotaxy syndrome and prenatal drug exposure to follitropin-alfa (5.6% vs. 1.1%; p = 0.04), and drugs used in nicotine dependence (3.7% vs. 0.2%; p = 0.02). Five mothers used PTU during pregnancy and gave birth to a child with trisomy 18, renal abnormalities, or hypospadias and cardiac defects. Conclusion: This study identified follitropin-alfa and drugs used in nicotine dependence as possible teratogens of heterotaxy syndrome. Our data suggest the possibility that there is an increased risk of birth defects (including renal, urological, and cardiac abnormalities) in children born among mothers taking PTU prenatally, but not for heterotaxy syndrome. (C) 2016 Wiley Periodicals, Inc.</p
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