- ID:
- ivo://CDS.VizieR/J/A+AS/126/373
- Title:
- IRON Project XXVII. Fe IV collision strengths
- Short Name:
- J/A+AS/126/373
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Collision strengths and maxwellian-averaged rate coefficients have been calculated for 8771 non-vanishing transitions among 140 fine structure levels, dominated by the configurations 3d^5^, 3d^4^4s, and 3d^4^4p in Fe IV. Collision strengths are calculated using the R-matrix method with a 49 term close-coupling target expansion for electron energies up to 15 rydbergs. Rate coefficients are tabulated for a wide range of temperatures in which Fe IV is abundant in plasma sources. A brief discussion of the calculations and sample results are given. The present rates for Fe IV are expected to find applications in spectral diagnostics of a variety of astrophysical sources.
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- ID:
- ivo://CDS.VizieR/J/A+AS/131/153
- Title:
- IRON Project XXXI. Fe XII electron excitation
- Short Name:
- J/A+AS/131/153
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The following tables list energy levels and electron excitation data for the lowest 41 levels of Fe XII (configurations 3s^2^ 3p^3, 3s 3p^4^ and 3s^2 ^3p^2^ 3d). The table numbers correspond to the numbering given in the paper
- ID:
- ivo://CDS.VizieR/J/A+AS/135/159
- Title:
- IRON Project. XXXIII.
- Short Name:
- J/A+AS/135/159
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Radiative decay rates are computed with the atomic structure code superstructure for the 2s2p^3^ ^5^S^o^_2_ - 2s^2^2p^2^ ^3^P_1_, ^3^P_2_ and ^1^D_2_ intercombination transitions of the carbon isoelectronic sequence (6<=Z<=28). Contributions from configuration interaction and relativistic corrections are carefully studied, in particular the spin-spin interaction that is shown to be of considerable importance for low Z. By extensive comparisons with other theoretical datasets and measurements of the ^5^S^o^_2_ radiative lifetime and the B=A(^5^S^o^_2_-^3^P_2_)/A(^5^S^o^_2_-^3^P_1_) branching ratio, we are able to assign accuracy ratings to the present transition probabilities. The transitions to the ground term are believed to be accurate to better than 10% whereas the smaller A-values belonging to transitions to the ^1^D_2_ are not expected to be accurate to more than 20%. ***************************************************************************** * * * The author(s) did not provide their tables as announced in the paper. * * Only some of the published tables are here. * * * *****************************************************************************
- ID:
- ivo://CDS.VizieR/J/A+AS/135/347
- Title:
- IRON Project XXXV. Fe XXIV and Fe XXV
- Short Name:
- J/A+AS/135/347
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The first large-scale calculations of relativistic radiative transition probabilities from the Iron Project is reported for dipole allowed and intercombination (E1) transitions in Li-like Fe XXIV and He-like Fe XXV. The ab intio calculations are carried out in the close coupling approximation using the Breit-Pauli R-matrix method in intermediate coupling characterized by SLJ, with total (2S+1)=2,4, L=7, J=1/2-11/2 even and odd parity, for Fe XXIV, and with total (2S+1)=1,3, L=9, and J=0-4 for Fe XXV. The eigenfunction expansions for the target ions include 13 levels up to the n=3 for Fe XXV, and 16 levels up to the n=4 for Fe XXVI, respectively. The calculated number of bound levels, 83 for Fe XXIV and 138 for Fe XXV, is much larger than experimentally observed. The level energies are in good agreement for the common levels. All dipole and intercombination fine structure transitions involving the calculated bound levels up to n=10 and l=5 or 6 are considered. Oscillator strengths, line strengths, and Einstein A-coefficients are tabulated for 802 transitions in Fe XXIV and 2579 transitions in Fe XXV. The results compare well with limited subsets of transitions considered in previous works including fully relativistic and QED corrections. Additional comparisons between the length and the velocity formulations indicate an overall accuracy between 1-10%. The range of uncertainty is indicative of the relatively small influence of atomic effects, such as the two-body Breit interaction terms and finite nuclear mass term, that are not included in the Breit-Pauli approximation employed in the present calculations. The extensive set of data is expected to be useful in the analysis of X-ray and XUV spectra from astrophysical sources.
- ID:
- ivo://CDS.VizieR/J/A+AS/136/395
- Title:
- IRON Project XXXVII. Fe VI collision strengths
- Short Name:
- J/A+AS/136/395
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Collision strengths and Maxwellian-averaged rate coefficients have been calculated for 3,160 non-vanishing transitions among 80 fine structure levels, dominated by configurations 3d^3^, 3d^2^4s, and 3d^2^4p in Fe VI. Collision strengths are calculated using the R-matrix method with a 34-term close-coupling target expansion and for electron energies up to 10 Rydbergs. Detailed comparisons of rate coefficients are presented with the relativistic Breit-Pauli calculations using a 19-level expansion corresponding to the first 8 LS terms dominated by the ground configuration 3d^3^. For the low-lying transitions of practical interest there is excellent agreement, better than 10%, among three sets of rate coefficients calculated using 34 term and 8-term non-relativistic calculations and the 19-level Breit-Pauli calculation, indicating that (i) the relativistic effects are not too significant, and (ii) the numerical uncertainties associated with the resolution of the extensive resonances in the collision strengths are small. Rate coefficients are tabulated in a range of temperatures, 10^4^-10^6^K, where Fe VI is normally abundant in radiatively photoionized or collisionally ionized plasmas sources. The present rates for Fe VI are expected to find applications in UV spectral diagnostics of hot stellar sources and planetary nebulae.
- ID:
- ivo://CDS.VizieR/J/A+AS/137/165
- Title:
- IRON Project XXXVIII. Fe XV
- Short Name:
- J/A+AS/137/165
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- As part of a systematic study of the collisional properties of Fe ions carried out by the IRON Project, electron excitation rates (effective collision strengths) are computed for all the fine-structure transitions within the n=3 complex of Fe XV in the electron temperature range 10^5^<=T/K<=10^7^. Configuration-interaction target wavefunctions are generated with the atomic structure code superstructure, and collision strengths are computed in the close-coupling approximation with a Breit-Pauli R-matrix package. Special care is taken to resolve the resonance structure and to ensure the convergence of the partial wave expansion, specially for dipole allowed transitions. By comparing with previously calculated collision strengths in the distorted wave approximation, a 20% accuracy rating is assigned to transitions with effective collision strengths {Upsilon}(T)>10^-2^.
- ID:
- ivo://CDS.VizieR/J/ApJ/729/94
- Title:
- IR spectroscopy of PAH in 6-15{mu}m band
- Short Name:
- J/ApJ/729/94
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Polycyclic aromatic hydrocarbon (PAH) growth and destruction are thought to proceed via the occasional incorporation of five- and seven-membered fused ring defects in the hexagonal carbon skeleton. Using density functional theory, this paper investigates the effect such five- and seven-membered fused ring defects have on the infrared spectra of ovalene (OV; C_32_H_14_), circumovalene (c-OV; C_66_H_20_), and circumcircumovalene (cc-OV; C_112_H_26_). The defects make only small changes to the overall infrared (IR) spectra, both in the mid-IR and in the far-IR, of these species. In addition to small shifts in the positions of the bands between the PAHs with and without defects, the most common effect of the defects is to increase the number of bands. Except for an anion with the Stone-Wales defect, all of the species studied have the C-C stretching band at 6.3um or at longer wavelengths, the position in Classes B and C astronomical PAH spectra. In the case of the Stone-Wales anion, the band falls at 6.20um, suggesting that further study of defects is probably worthwhile, as some PAHs with defects might be important in those sources (Class A) that show a C-C stretching band that falls near 6.2um.
- ID:
- ivo://CDS.VizieR/J/ApJ/825/96
- Title:
- IR spectrum of protonated ovalene (7-C_32_H_15_^+^)
- Short Name:
- J/ApJ/825/96
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The mid-infrared emission from galactic objects, including reflection nebulae, planetary nebulae, proto-planetary nebulae, molecular clouds, etc, as well as external galaxies, is dominated by the unidentified infrared (UIR) emission bands. Large protonated polycyclic aromatic hydrocarbons (H^+^PAHs) were proposed as possible carriers, but no spectrum of an H^+^PAH has been shown to exactly match the UIR bands. Here, we report the IR spectrum of protonated ovalene (7-C_32_H_15_^+^) measured in a para-hydrogen (p-H_2_) matrix at 3.2K, generated by bombarding a mixture of ovalene and p-H_2_ with electrons during matrix deposition. Spectral assignments were made based on the expected chemistry and on the spectra simulated with the wavenumbers and infrared intensities predicted with the B3PW91/6-311++G(2d,2p) method. The close resemblance of the observed spectral pattern to that of the UIR bands suggests that protonated ovalene may contribute to the UIR emission, particularly from objects that emit Class A spectra, such as the IRIS reflection nebula, NGC 7023.
- ID:
- ivo://CDS.VizieR/J/ApJS/195/24
- Title:
- IR spectrum of Uranium hollow cathode lamps
- Short Name:
- J/ApJS/195/24
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We provide new measurements of wavenumbers and line identifications of 10100 UI and UII near-infrared (NIR) emission lines between 2500cm^-1^ and 12000cm^-1^ (850-4000nm) using archival Fourier transform spectrometer spectra from the National Solar Observatory. This line list includes isolated uranium lines in the Y, J, H, K, and L bands (0.9-1.1um, 1.2-1.35um, 1.5-1.65um, 2.0-2.4um, and 3.0-4.0um, respectively), and provides six times as many calibration lines as thorium in the NIR spectral range. The line lists we provide enable inexpensive, commercially available uranium hollow cathode lamps to be used for high-precision wavelength calibration of existing and future high-resolution NIR spectrographs.
- ID:
- ivo://CDS.VizieR/J/ApJS/233/24
- Title:
- Iso-propyl cyanide rotational study
- Short Name:
- J/ApJS/233/24
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A detailed analysis of the rotational spectra of the interstellar iso-propyl cyanide has been carried out up to 480GHz using three different high-resolution spectroscopic techniques. Jet-cooled broadband chirped pulse Fourier transform microwave spectroscopy from 6 to 18GHz allowed us to measure and analyze the ground-state rotational transitions of all singly substituted ^13^C and ^15^N isotopic species in their natural abundances. The monohydrate of iso-propyl cyanide, in which the water molecule bounds through a stronger O-H...N and weaker bifurcated (C-H)_2_...O hydrogen bonds in a C_s_ configuration, has also been detected in the supersonic expansion. Stark-modulation spectroscopy in the microwave and millimeter wave range from 18 to 75GHz allowed us to analyze the vibrational satellite pattern arising from pure rotational transitions in the low-lying vibrational excited states. Finally, assignments and measurements were extended through the millimeter and submillimeter wave region. The room temperature rotational spectra made possible the assignment and analysis of pure rotational transitions in 19 vibrationally excited states. Significant perturbations were found above 100GHz in most of the observed excited states. Due to the complexity of the interactions and importance of this astrophysical region for future radioastronomical detection, both a graphical plot approach and a coupled fit have been used to assign and measure almost 10000 new lines.
