Kramers–Kronig transforms calculation with a fast convolution algorithm

Bruzzoni, P.; Carranza, Ricardo M.; Collet-Lacoste, J.R.; Crespo, E.

doi:10.1016/s0013-4686(02)00677-1

Cited by 32 publications

(23 citation statements)

References 15 publications

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“…The real part of the refractive index is then calculated by using a numerical solution to the Kramers-Kronig relations (Bohren 2010). The method used for this calculation is the same as in Z17, namely the fast Fourier transform (FFT) routines, as described in Bruzzoni et al (2002). We used Mie theory (Mie 1908) to calculate the extinction efficiency at each wavelength and grain size.…”

Section: Extinction Cross Sectionsmentioning

confidence: 99%

Dust absorption and scattering in the silicon K-edge

Zeegers

Costantini

Rogantini

et al. 2019

A&A

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Context. The composition and properties of interstellar silicate dust are not well understood. In X-rays, interstellar dust can be studied in detail by making use of the fine structure features in the Si K-edge. The features in the Si K-edge offer a range of possibilities to study silicon-bearing dust, such as investigating the crystallinity, abundance, and the chemical composition along a given line of sight. Aims. We present newly acquired laboratory measurements of the silicon K-edge of several silicate-compounds that complement our measurements from our earlier pilot study. The resulting dust extinction profiles serve as templates for the interstellar extinction that we observe. The extinction profiles were used to model the interstellar dust in the dense environments of the Galaxy. Methods. The laboratory measurements, taken at the Soleil synchrotron facility in Paris, were adapted for astrophysical data analysis and implemented in the SPEX spectral fitting program. The models were used to fit the spectra of nine low-mass X-ray binaries located in the Galactic center neighborhood in order to determine the dust properties along those lines of sight.Results. Most lines of sight can be fit well by amorphous olivine. We also established upper limits on the amount of crystalline material that the modeling allows. We obtained values of the total silicon abundance, silicon dust abundance, and depletion along each of the sightlines. We find a possible gradient of 0.06 ± 0.02 dex/kpc for the total silicon abundance versus the Galactocentric distance. We do not find a relation between the depletion and the extinction along the line of sight.

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Section: Extinction Cross Sectionsmentioning

confidence: 99%

Dust absorption and scattering in the silicon K-edge

Zeegers

Costantini

Rogantini

et al. 2019

A&A

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“…In this paper, we use a numerical method using the fast Fourier transform routines (FFT) as described in Bruzzoni et al (2002). An example of the real and the imaginary part of the refractive index of sample 1 (olivine) is shown in Figure 3.…”

Section: Optical Constantsmentioning

confidence: 99%

Absorption and scattering by interstellar dust in the silicon K-edge of GX 5-1

Zeegers

Costantini

Vries

et al. 2017

A&A

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Context. We study the absorption and scattering of X-ray radiation by interstellar dust particles, which allows us to access the physical and chemical properties of dust. The interstellar dust composition is not well understood, especially on the densest sight lines of the Galactic Plane. X-rays provide a powerful tool in this study. Aims. We present newly acquired laboratory measurements of silicate compounds taken at the Soleil synchrotron facility in Paris using the Lucia beamline. The dust absorption profiles resulting from this campaign were used in this pilot study to model the absorption by interstellar dust along the line of sight of the low-mass X-ray binary (LMXB) GX 5-1. Methods. The measured laboratory cross-sections were adapted for astrophysical data analysis and the resulting extinction profiles of the Si K-edge were implemented in the SPEX spectral fitting program. We derive the properties of the interstellar dust along the line of sight by fitting the Si K-edge seen in absorption in the spectrum of GX 5-1. Results. We measured the hydrogen column density towards GX 5-1 to be 3.40 ± 0.1 × 10 22 cm −2 . The best fit of the silicon edge in the spectrum of GX 5-1 is obtained by a mixture of olivine and pyroxene. In this study, our modeling is limited to Si absorption by silicates with different Mg:Fe ratios. We obtained an abundance of silicon in dust of 4.0 ± 0.3 × 10 −5 per H atom and a lower limit for total abundance, considering both gas and dust, of > 4.4 × 10 −5 per H atom, which leads to a gas to dust ratio of > 0.22. Furthermore, an enhanced scattering feature in the Si K-edge may suggest the presence of large particles along the line of sight.

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“…47,49,50 (Similarly to the atomic scattering factor files, 47,48 f 1 values at photon energies below 29 eV are set to −9999 in order to reflect the fact that the calculated f 1 values are not reliable in this photon energy range.) (3) to calculate the element-derived values based on the molecular formulae, i.e., elemental ratios.…”

Section: Data Processingmentioning

confidence: 99%

Calibrated NEXAFS spectra of common conjugated polymers

Watts

Swaraj

Nordlund

et al. 2011

The Journal of Chemical Physics

119

111

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Near edge x-ray absorption fine structure (NEXAFS) spectroscopy has evolved into a powerful characterization tool for polymeric materials and is increasingly being used to elucidate composition and orientation in thin films of relevance to organic electronic devices. For accurate quantitative compositional analysis, insight into the electronic structure and the ability to assess molecular orientation, reliable reference spectra with known energy resolution and calibrated energy scale are required. We report a set of such NEXAFS spectra from 23 semiconducting polymers and some related materials that are frequently used in organic device research.

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Kramers–Kronig transforms calculation with a fast convolution algorithm

Cited by 32 publications

References 15 publications

Dust absorption and scattering in the silicon K-edge

Dust absorption and scattering in the silicon K-edge

Absorption and scattering by interstellar dust in the silicon K-edge of GX 5-1

Calibrated NEXAFS spectra of common conjugated polymers

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