- ID:
- ivo://CDS.VizieR/J/A+AS/129/155
- Title:
- Si XI & Si XIII lines Stark broadening
- Short Name:
- J/A+AS/129/155
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using a semiclassical perturbation approach, we have calculated electron-, proton-, and He III-impact line widths and shifts for 4 Si XI multiplets for perturber densities 10^18^-10^23^cm^-3^ and temperatures T=500000-4000000K, and for 61 Si XIII multiplets for perturber densities 10^16^-10^23^cm^-3^ and temperatures T=500000-6000000K. For lower perturber densities, obtained results are linear with perturber density.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/ApJS/239/30
- Title:
- S-like ions from Cr IX to Cu XIV transitions
- Short Name:
- J/ApJS/239/30
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a consistent set of calculated energies and E1, M1, E2, M2 radiative transition data for the main n=3 levels from the 3s^2^3p^4^, 3p^6^, 3s3p^4^3d, 3s^2^3p^2^3d^2^, 3s3p^5^, 3s^2^3p^3^3d, and 3s3p^3^3d^2^ configurations for S-like ions from CrIX to CuXIV. The fully relativistic multiconfiguration Dirac-Hartree-Fock method implemented in the GRASP2K code (Jonsson+ 2007CoPhC.177..597J ; 2013CoPhC.184.2197J) is used to perform the present calculations. The excitation energies of the lowest 47 levels from the 3s^2^3p^4^, 3s3p^5^, and 3s^2^3p^3^3d configurations, producing the strongest lines, are found to be in good agreement, reaching spectroscopic accuracy, with the latest experimental values for FeXI evaluated by Del Zanna. Our energies can reliably be used to identify in astrophysical and laboratory spectra the 3s^2^3p^3^3d levels in other S-like ions, which are mostly unknown. On the contrary, significant discrepancies with the 3s3p^4^3d levels were found, emphasizing the need for more detailed experimental studies. A few new tentative identifications are suggested. The benchmarks we present indicate that our consistent set of radiative data is accurate and can be used for spectral line modeling.
- ID:
- ivo://CDS.VizieR/J/A+A/625/A29
- Title:
- Slow collisions of O6+ with H cross section
- Short Name:
- J/A+A/625/A29
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The electron capture in collisions of highly charged O6^+^ ions with ground state hydrogen atom is a very important process in the solar wind X-ray studies. In the present study, the full quantum-mechanical molecular-orbital close-coupling (QMOCC) method is employed to study electron capture reactions in collisions of O6+ion with the ground state atomic hydrogen in the energy region from 10^-4^keV/u to 5keV/u. The ab initio multi-reference single and double excitation configuration interaction (MRD-CI) method is used to calculate the potential and coupling data used in the QMOCC calculations. Total and state-selective cross sections for the dominant and subdominant reaction channels are calculated and compared with the available experimental and theoretical data. The branching ratios for Lithium-like O^5+^ excited ions are used to calculate the contribution of cascade radiative transitions from n=5 levels to the population of 4l states. From the calculated cross sections, reaction rate coefficients are obtained for temperatures between 1000 and 1x10^9^K and compared with other calculations.
- ID:
- ivo://CDS.VizieR/J/A+A/422/1109
- Title:
- SnII Lifetimes and oscillator strengths
- Short Name:
- J/A+A/422/1109
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Oscillator strengths calculated for 101 lines of Sn II arising from auto-ionized levels are displayed in column three of Table A1, while columns one and two give the transitions and corresponding wavelengths, respectively. In the second column of Table A2, we present the radiative lifetimes calculated for 13 levels of Sn II. Two levels correspond to 5s2 4f 2F5/2 5s2 4f 2F7/2 for both theoretical and experimental values obtained by other authors. In the other columns of Table 2 we present these values. A good agreement exists between our work and the experimental values. The eleven remaining values correspond to the levels labeled by Moore as 1{deg} at 11{deg} and whose identification is based on the IC 5p3-5s5p5d-5s5p6s.
- ID:
- ivo://CDS.VizieR/J/A+A/626/A34
- Title:
- SO2 and N-ethylformamide lines
- Short Name:
- J/A+A/626/A34
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a new experimental set-up devoted to the study of gas phase molecules and processes using broadband high spectral resolution rotational spectroscopy. A reactor chamber is equipped with radio receivers similar to those used by radio astronomers to search for molecular emission in space. The whole range of the Q (31.5-50GHz) and W bands (72-116.5GHz) is available for rotational spectroscopy observations. The receivers are equipped with 16x2.5GHz fast Fourier transform spectrometers with a spectral resolution of 38.14 kHz allowing the simultaneous observation of the complete Q band and one-third of the W band. The whole W band can be observed in three settings in which the Q band is always observed. Species such as CH_3_CN, OCS, and SO_2_ are detected, together with many of their isotopologues and vibrationally excited states, in very short observing times. The system permits automatic overnight observations, and integration times as long as 2.4x10^5^ seconds have been reached. The chamber is equipped with a radiofrequency source to produce cold plasmas, and with four ultraviolet lamps to study photochemical processes. Plasmas of CH_4_, N_2_, CH_3_CN, NH_3_, O_2_, and H_2_, among other species, have been generated and the molecular products easily identified by the rotational spectrum, and via mass spectrometry and optical spectroscopy. Finally, the rotational spectrum of the lowest energy conformer of CH_3_CH_2_NHCHO (N-ethylformamide), a molecule previously characterized in microwave rotational spectroscopy, has been measured up to 116.5GHz, allowing the accurate determination of its rotational and distortion constants and its search in space.
- ID:
- ivo://CDS.VizieR/J/A+A/347/348
- Title:
- Solar abundance of iron
- Short Name:
- J/A+A/347/348
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Numerous papers on the solar photospheric abundance of iron have recently been published leading to a longstanding debate concerning rather different results obtained from the analyses of Fe I lines and, to a lesser extent, of Fe II lines. Based on a set of 65 solar Fe I lines, with accurate transition probabilities as well as new accurate damping constants, we construct a new empirical photospheric model. We succeed to reconcile abundance results obtained from low and high excitation Fe I lines as well as from Fe II lines and derive a solar photospheric abundance of iron, A_Fe_=7.50+/-0.05, which perfectly agrees with the meteoritic value.
- ID:
- ivo://CDS.VizieR/J/ApJS/210/12
- Title:
- Solar photoionization rates
- Short Name:
- J/ApJS/210/12
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Extreme UV (EUV) spectra from the Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED)/Solar EUV Experiment are used to infer photoionization rates in the inner heliosphere. Relating these rates to various proxies describing the solar EUV radiation, we construct a multi-linear model which allows us to extrapolate ionization rates back to periods when no routine measurements of the solar EUV spectral distribution have been available. Such information is important, e.g., for comparing conditions of the interstellar neutral particles in the inner heliosphere at the time of Ulysses/GAS observations with conditions during the more recent observations of the Interstellar Boundary Explorer. From a period of 11 yr when detailed spectra from both TIMED and three proxies -- Solar and Heliospheric Observatory/CELIAS/SEM-rates, F10.7 radio flux, and Mg II core-to-wing indices -- have been available, we conclude that the simple model is able to reproduce the photoionization rates with an uncertainty of typically 5%.
- ID:
- ivo://CDS.VizieR/J/ApJS/233/16
- Title:
- Spectral data for neutral carbon (C I)
- Short Name:
- J/ApJS/233/16
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this critical compilation, all experimental data on the spectrum of neutral carbon known to us were methodically evaluated and supplemented by parametric calculations with Cowan's codes. The sources of experimental data vary from laboratory to astrophysical objects, and employ different instrumentations, from classical grating and Fourier transform spectrometers to precise laser spectroscopy setups and various other modern techniques. This comprehensive evaluation provides accurate atomic data on energy levels and wavelengths (observed and Ritz) with their estimated uncertainties, as well as a uniform description of the observed line intensities. In total, 412 previously known energy levels were optimized with the help of 1221 selected best-observed lines participating in 1365 transitions in the wavelength region 750{AA}-609.14{mu}m. The list of recommended energy levels is extended by including 21 additional levels found through quantum-defect extrapolations or parametric calculations with Cowan's codes. In addition, 737 possibly observable transitions are predicted. Critically evaluated transition probabilities for 1616 lines are provided, of which 241 are new. With accurate energy levels obtained, combined with additional observed data on high Rydberg states, the ionization limit was determined to be 90820.348(9)cm-1 or 11.2602880(11)eV, in fair agreement with the previously recommended value, but more accurate.
- ID:
- ivo://CDS.VizieR/J/A+A/600/A44
- Title:
- Spectral line list of hydantoin
- Short Name:
- J/A+A/600/A44
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Hydantoin (Imidazolidine-2, 4-dione, C_3_H_4_N_2_O_2_) is a five-membered heterocyclic compound that is known to arise from prebiotic molecules such as glycolic acid and urea, and to give the simplest amino acid, glycine, by hydrolysis under acidic condition. The gas chromatography combined with the mass spectrometry of carbonaceous chondrites lead to the detection of this molecule as well as several kinds of amino acids. The lack of spectroscopic information, especially on the rotational constants, has prevented us from conducting a search for hydantoin in interstellar space. If a rotational temperature of 100K is assumed as the kinetic temperature of a star-forming region, the spectral intensity is expected to be at its maximum in the millimeter-wave region. Laboratory spectroscopy of hydantoin in the millimeter-wave region is the most important in providing accurate rest frequencies to be used for astronomical research. Pure rotational spectra of hydantoin were observed in the millimeter-wave region using the frequency modulated microwave spectrometer at Toho University. Solid hydantoin was heated to around 150{deg}C to provide appropriate vapor pressure. Quantum chemical calculations suggest that the permanent dipole moment of this molecule lies almost along the b-molecular axis, so that spectral search for b-type R-branch transition has been conducted.
- ID:
- ivo://CDS.VizieR/J/A+A/645/A136
- Title:
- Spectral properties for Fluorine-like Ions
- Short Name:
- J/A+A/645/A136
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The primary motivation of this paper is to provide accurate atomic properties of F-like ions with Z=20-30, including energy levels, line strengths, static dipole polarizabilities, and lifetimes. In addition, a detailed analysis is also carried out to explore the convergence and uncertainties of our results. Large-scale B-spline relativistic configuration interaction calculations are carried out to generate the atomic properties of F-like ions. The radial parts of one-electron Dirac orbitals are obtained from the relativistic self-consistent field procedure in which the Breit Interaction and QED corrections (vacuum polarization and self-energy terms) are also included. A numerical method, called Emu CI, is adopted to decrease the size of CI matrix significantly without loss of much accuracy. Energy levels and line strengths for electric-dipole (E1), electric-quadrupole (E2), and magnetic-dipole (M1) transitions are provided for the 250 lowest levels of each system, showing a good agreement with available theoretical and experimental information. The static dipole polarizabilities and lifetimes for the ten lowest states are also reported. A statement for the convergence and uncertainties of our results is presented.
