Electron Impact Ionization of C+, N+and P+Ions

Yamada, I.; Danjo, A; Hirayama, T.; Matsumoto, Atsushi; Ohtani, S.; Suzuki, Hiroshi; Takayanagi, Toshiyuki; Tawara, H.; Wakiya, K.; Yoshino, Masafumi

doi:10.1143/jpsj.58.1585

Cited by 31 publications

(28 citation statements)

References 4 publications

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“…The data of Aitken et al (1971) for C ii are slightly higher than the measurements of Yamada et al (1989a), especially near the threshold. Nevertheless, we use both data sets in our fit, with a larger weight given to the data of Yamada et al…”

Section: Di: 2p Cross-sectionscontrasting

confidence: 58%

“…The data of Yamada et al (1989a) for O ii are about 5% higher than the older data of Aitken et al (1971); our fit lies between both sets of measurements. For O ii and Ne iv, the high energy measurements of Donets & Ovsyannikov (1981) are significantly higher than our fit, including that data set; we have therefore discarded these measurements for these ions.…”

Section: Di: 2p Cross-sectionsupporting

confidence: 46%

“…The elements of the B-like sequence (1s 2 2s 2 2p) have an EA contribution in the outer shell that is relatively small (Yamada et al 1989a;Duponchelle et al 1997;Loch et al 2003).…”

Section: The B Isoelectronic Sequencementioning

confidence: 99%

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X-ray emission from thin plasmas

Urdampilleta

Kaastra

Mehdipour

2017

A&A

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Every observation of astrophysical objects involving a spectrum requires atomic data for the interpretation of line fluxes, line ratios, and ionization state of the emitting plasma. One of the processes that determines it is collisional ionization. In this study, an update of the direct ionization (DI) and excitation-autoionization (EA) processes is discussed for the H to Zn-like isoelectronic sequences. In recent years, new laboratory measurements and theoretical calculations of ionization cross-sections have become available. We provide an extension and update of previous published reviews in the literature. We include the most recent experimental measurements and fit the cross-sections of all individual shells of all ions from H to Zn. These data are described using an extension of Younger's and Mewe's formula, suitable for integration over a Maxwellian velocity distribution to derive the subshell ionization rate coefficients. These ionization rate coefficients are incorporated in the high-resolution plasma code and spectral fitting tool SPEX V3.0.

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Section: Di: 2p Cross-sectionscontrasting

confidence: 58%

Section: Di: 2p Cross-sectionsupporting

confidence: 46%

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X-ray emission from thin plasmas

Urdampilleta

Kaastra

Mehdipour

2017

A&A

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“…Experimental cross sections from Brook et al (1978) and Yamada et al (1989) are adopted for the collisional ionization of the ground states of C i and C ii. The authors expect uncertainties of <30% and <20%, respectively, for the data at low energies, with significant improvements in the accuracy at higher energies.…”

Section: Collisional Transitionsmentioning

confidence: 99%

Non-LTE line-formation for neutral and singly-ionized carbon

Przybilla

Butler

Kudritzki

2001

A&A

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Abstract. A comprehensive model atom for non-LTE line-formation calculations for neutral and singly-ionized carbon is presented. Highly accurate radiative and collisional atomic data are incorporated, recently determined for astrophysical and fusion research using the R-matrix method in the close-coupling approximation. As a test and first application of the model, carbon abundances are determined on the basis of line-blanketed LTE model atmospheres for five stars, the main sequence object Vega (A0 V) and the supergiants η Leo (A0 Ib), HD 111613 (A2 Iabe), HD 92207 (A0 Iae) and β Ori (B8 Iae), using high S/N and high-resolution spectra at visual and near-IR wavelengths. The computed non-LTE line profiles fit the observations well for a single carbon abundance in each object. For two supergiants, η Leo and HD 111613, lines of both species are simultaneously present in the spectra, giving consistent C i and C ii abundances (within the error bars). However, the uncertainties of the abundances are large, on the order of ∼0.3 dex (statistical + systematical error), thus the ionization equilibrium of C i/ii is of restricted use for the determination of stellar parameters. All supergiants within our sample show a depletion of carbon on the order of 0.2-0.5 dex, indicating the mixing of CN-cycled material into the atmospheric layers, with the sum of the CNO abundances remaining close to solar. This finding is in accordance with recent stellar evolution models accounting for mass-loss and rotation. For Vega, an underabundance of carbon by 0.3 dex is found, in excellent agreement with the similar underabundance of other light elements. The dependence of the non-LTE effects on the atmospheric parameters is discussed and the influence of systematic errors is estimated. Special emphasis is given to the supergiants where a strong radiation field at low particle densities favours deviations from LTE. Non-LTE effects systematically strengthen the C i/ii lines. For the C i lines in the infrared, a strong sensitivity to modifications in the photoionization and collisional excitation data is found. An increasing discrepancy between our model predictions and the observations for the C ii doublet λλ 6578-82 is perceived with rising luminosity, while the other C ii doublet and quartet lines remain consistent. Furthermore, the influence of microturbulence on the statistical-equilibrium calculations is investigated.

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“…Both YSZ and CeO 2 layers show "cube-on-cube" orientation with respect to the Si substrate, while the STF film shows a 45° in-plane rotation of the lattice with respect to CeO 2 to allow a better lattice match. 14 The RMS roughness of this sample is also below 3nm as measured by AFM. -.…”

Section: Magnetooptical Film and Waveguide Characterizationmentioning

confidence: 72%

As 2 S 3 /Sr(Ti 0.7 Co 0.3 )O 3 and As 2 S 3 /Sr(Ti 0.6 Fe 0.4 )O 3 strip-loaded waveguides for integrated magneto-optical isolator applications

Kim

et al. 2009

SPIE Proceedings

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(001) substrates. Both materials were demonstrated to be magneto-optically active, and more optically transparent at 1550nm wavelength compared with other non-garnet ferromagnetic materials.As 2 S 3 /STF and As 2 S 3 /STC strip-loaded waveguides were fabricated on epitaxial STF or STC films grown on LSAT (001) substrates using thermal evaporation and lift-off processing. The absorption of STF at 1550 nm was measured by ellipsometry and by optical transmission spectrum measurements of the As 2 S 3 /STF waveguides, which gave similar results. A novel design for a Non-Reciprocal Phase Shift (NRPS) strip-loaded waveguide using chalcogenide glass (ChG) as the guiding layer is proposed. The NRPS and figure of merit of these waveguides are simulated. The ChG strip-loaded waveguide structure shows advantages both in fabrication and device performance according to the simulation results.Our study suggests the possibility of magneto-optical magneto-optical isolators monolithically integrated on a silicon platform.

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Electron Impact Ionization of C⁺, N⁺and P⁺Ions

Cited by 31 publications

References 4 publications

X-ray emission from thin plasmas

X-ray emission from thin plasmas

Non-LTE line-formation for neutral and singly-ionized carbon

As 2 S 3 /Sr(Ti 0.7 Co 0.3 )O 3 and As 2 S 3 /Sr(Ti 0.6 Fe 0.4 )O 3 strip-loaded waveguides for integrated magneto-optical isolator applications

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