X-ray spectroscopic identification of strain and structure-based resonances in a series of saturated carbon-cage molecules: Adamantane, twistane, octahedrane, and cubane

ABSTRACTAnnealing of nanodiamond at moderate temperature makes it possible to produce structures being intermediate in the carbon transformation from sp3- to sp2-state (graphite/diamond nanocomposites) and onion-like carbon (OLC). Electron microscopy shows such structures involve cage shells with spacing close to graphite. X-ray emission spectroscopy has been applied to examine the electronic structure of OLC and graphite/diamond nanocomposites. The CKα-spectra of OLC produced in the temperature range of 1600-1900 K were found to be markedly different from the spectrum of particles formed at 2140 K and characterized by better ordering of graphitic shells. The latter spectrum was shown to be very similar to the CKα-spectrum of polycrystalline graphite, while the former ones exhibited a significant increase of high-energy maximum that might be caused by the holed defect structure of graphitic networks forming at the intermediate annealing temperatures. To interpret experimental spectra, the quantum-chemical semiempirical AM1 calculation of icosahedral C540 cage and that with holed defects was carried out. The lack of at least 22% atoms in an internal carbon cage was found to be essential to provide an increase of density of high-energy electronic states similar to that observed in the spectrum of OLC produced at 1900 K.

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Electronic Effects of Adducts on C60: A Molecular Orbital Analysis

MRS Proceedings ◽

10.1557/proc-247-379 ◽

1992 ◽

Vol 247 ◽

Author(s):

Y. C. Fann ◽

D. Singh ◽

S. A. Jansen

Keyword(s):

Molecular Orbital ◽

Alkali Metals ◽

Theoretical Work ◽

Electronic Effects ◽

Cage Structure ◽

Carbon Cage ◽

X Ray ◽

Potential Applications ◽

Molecular Orbital Analysis ◽

Orbital Analysis

ABSTRACTBuckmisterfullerene, C60, has attracted great interest because of its carbon-cage structure and potential applications in the field of superconductivity when doped with alkali metals. The icosahedral framework of C60 has been confirmed by X-ray analysis of an osmylated C60, called ‘Bunnyball’. Little theoretical work has been done to understand the electronic mechanism of C60 and substituted C60. This work has focused on electronic properties of C60 and the bunnyball with hypothetical analogs metal substitutions to understand the electronic effects of adducts on the bunnyball. In this analysis, the osmylated C60and hypothetical analogs were studied by extended Hückel methods. Molecular orbital(MO) interaction diagrams constructed from Density of States (DOS) analysis of the bunnyballs are presented. The results suggest electronic effects induced by substitution /adduct strongly affect electronic population in the C60 unit.

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Density diagnostic of highly ionized samarium laser produced plasma using Ni-like spatially resolved spectra

Laser and Particle Beams ◽

10.1017/s0263034610000765 ◽

2011 ◽

Vol 29 (1) ◽

pp. 61-67 ◽

Cited By ~ 5

Author(s):

E. Louzon ◽

Z. Henis ◽

I. Levy ◽

G. Hurvitz ◽

Y. Ehrlich ◽

...

Keyword(s):

Electron Density ◽

Ionization State ◽

Plasma Parameters ◽

Hydrodynamic Simulations ◽

X Ray ◽

Spatially Resolved ◽

Laser Produced Plasma ◽

Hebrew University ◽

Spectroscopic Identification ◽

Measured Line

AbstractDetailed spectroscopic identification and analysis of lines emitted by Ni-like ions may infer on plasma parameters, such as electron density, temperature, and ionization state. Spatially, resolved X-ray spectra of samarium laser produced plasma were recorded in the 7 to10 Å wavelength range. Measured line intensity ratios of Ni-like 3d-5f, 3p-4d, 3p-4s, and 3s-4p transitions were used for electron density diagnostic as a function of the distance from the target. Calculations using Hebrew University Lawrence Livermore Atomic Code show that these ratios are not very sensitive to the electron temperature in the range from 500 to 1000 eV. Self-absorption of some lines is found to be important at electron densities higher than 1021cm−3. The inferred ranges of electron density and temperature are found to be consistent with results of hydrodynamic simulations and models of ionization in plasma.

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The MUSE-Wide Survey: survey description and first data release

Astronomy and Astrophysics ◽

10.1051/0004-6361/201834656 ◽

2019 ◽

Vol 624 ◽

pp. A141 ◽

Cited By ~ 20

Author(s):

T. Urrutia ◽

L. Wisotzki ◽

J. Kerutt ◽

K. B. Schmidt ◽

E. C. Herenz ◽

...

Keyword(s):

Emission Line ◽

High Redshift ◽

Complete Agreement ◽

Photometric Redshifts ◽

X Ray ◽

Data Release ◽

Spectroscopic Identification ◽

Deep Fields ◽

Luminous Objects ◽

Stellar Masses

We present the MUSE-Wide survey, a blind, 3D spectroscopic survey in the CANDELS/GOODS-S and CANDELS/COSMOS regions. The final survey will cover 100 × 1 arcmin2 MUSE fields. Each MUSE-Wide pointing has a depth of one hour and hence targets more extreme and more luminous objects over ten times the area of the MUSE-Deep fields. The legacy value of MUSE-Wide lies in providing “spectroscopy of everything” without photometric pre-selection. We describe the data reduction, post-processing and PSF characterization of the first 44 CANDELS/GOODS-S MUSE-Wide pointings released with this publication. Using a 3D matched filtering approach we detect 1602 emission line sources, including 479 Lyman-α (Lyα) emitting galaxies with redshifts 2.9 ≲ z ≲ 6.3. We cross-matched the emission line sources to existing photometric catalogs, finding almost complete agreement in redshifts (photometric and spectroscopic) and stellar masses for our low redshift (z < 1.5) emitters. At high redshift, we only find ∼55% matches to photometric catalogs. We encounter a higher outlier rate and a systematic offset of Δz ≃ 0.2 when comparing our MUSE redshifts with photometric redshifts from the literature. Cross-matching the emission line sources with X-ray catalogs from the Chandra Deep Field South, we find 127 matches, mostly in agreement with the literature redshifts, including ten objects with no prior spectroscopic identification. Stacking X-ray images centered on our Lyα emitters yields no signal; the Lyα population is not dominated by even low luminosity AGN. Other cross-matches of our emission-line catalog to radio and submillimeter data, yielded far lower numbers of matches, most of which already were covered by the X-ray catalog. A total of 9205 photometrically selected objects from the CANDELS survey lie in the MUSE-Wide footprint, of which we provide optimally extracted 1D spectra. We are able to determine the spectroscopic redshift of 98% of 772 photometrically selected galaxies brighter than 24th F775W magnitude. All the data in the first data release - datacubes, catalogs, extracted spectra, maps - are available on the MUSE-Wide data release webpage.

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