- ID:
- ivo://CDS.VizieR/J/A+AS/143/483
- Title:
- IRON Project XLII. Fe XXI
- Short Name:
- J/A+AS/143/483
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Effective collision strengths for transitions between 52 fine structure states calculated in a Breit-Pauli approximation are provided in ups.dat. Results are provided for logT in the range of 3.0-7.4 in steps of 0.1. The level indices refer to the ordering given in Table 2 text where the energies are also given. The format is most easily described by the fortran program provided - readups.f - which may be used to interface with user programs. Oscillator strengths for all dipole allowed transitions are provided in osc.dat which are also indexed with respect to Table 2.
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- ID:
- ivo://CDS.VizieR/J/A+AS/144/141
- Title:
- Iron Project. XLIII. Fe V
- Short Name:
- J/A+AS/144/141
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- An extensive set of dipole-allowed, intercombination, and forbidden transition probabilities for Fe V is presented. The Breit-Pauli R-matrix (BPRM) method is used to calculate 1.46x10^6^ oscillator strengths for the allowed and intercombination E1 transitions among 3865 fine-structure levels dominated by configuration complexes with n<=10 and l<=9. These data are complemented by an atomic structure configuration interaction (CI) calculation using the SUPERSTRUCTURE program for 362 relativistic quadrupole (E2) and magnetic dipole (M1) transitions among 65 low-lying levels dominated by the 3d^4^ and 3d^3^ 4s configurations. Procedures have been developed for the identification of the large number of fine-structure levels and transitions obtained through the BPRM calculations. The target ion Fe VI is represented by an eigenfunction expansion of 19 fine-structure levels of 3d^3^ and a set of correlation configurations. Fe V bound levels are obtained with angular and spin symmetries SL{pi} and J{pi} of the (e + Fe VI) system such that 2S+1=5, 3, 1, L<=10, J<=8 of even and odd parities. The completeness of the calculated dataset is verified in terms of all possible bound levels belonging to relevant LS terms and transitions in correspondence with the LS terms. The fine-structure averaged relativistic values are compared with previous Opacity Project LS coupling data and other works. The 362 forbidden transition probabilities considerably extend the available data for the E2 and M1 transitions, and are in good agreement with those computed by Garstang for the 3d^4^ transitions.
- ID:
- ivo://CDS.VizieR/J/A+AS/147/111
- Title:
- Iron Project. XLIV. Fe VI.
- Short Name:
- J/A+AS/147/111
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Relativistic atomic structure calculations for electric dipole (E1), electric quadrupole (E2) and magnetic dipole (M1) transition probabilities among the first 80 fine-structure levels of Fe VI, dominated by configurations 3d^3^, 3d^2^4s, and 3d^2^4p, are carried out using the Breit-Pauli version of the code SUPERSTRUCTURE. Experimental energies are used to improve the accuracy of these transition probabilities. Employing the 80-level collision-radiative (CR) model with these dipole and forbidden transition probabilities, and Iron Project R-matrix collisional data, we present a number of [Fe VI] line ratios applicable to spectral diagnostics of photoionized H II regions. It is shown that continuum fluorescent excitation needs to be considered in CR models in order to interpret the observed line ratios of optical [Fe VI] lines in planetary nebulae NGC 6741, IC 351, and NGC 7662. The analysis leads to parametrization of line ratios as function of, and as constraints on, the electron density and temperature, as well as the effective radiation temperature of the central source and a geometrical dilution factor. The spectral diagnostics may also help ascertain observational uncertainties. The method may be generally applicable to other objects with intensive background radiation fields, such as novae and active galactic nuclei. The extensive new Iron Project radiative and collisional calculations enable a consistent analysis of many line ratios for the complex iron ions.
374. IRON Project XLIX
- ID:
- ivo://CDS.VizieR/J/A+A/372/1078
- Title:
- IRON Project XLIX
- Short Name:
- J/A+A/372/1078
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Effective collision strengths for transitions between 86 fine structure states calculated in a Breit-Pauli approximation are provided in ups.dat. Results are provided for log T in the range of 5.0-7.6 in steps of 0.1. The level indices refer to the ordering given in Table 2 in the text where the energies are also given. The format is most easily described by the fortran program provided - readups.f - which may be used to interface with user programs. Oscillator strengths for all dipole allowed transitions are provided in osc.dat which are also indexed with respect to Table 2.
- ID:
- ivo://CDS.VizieR/J/A+AS/147/253
- Title:
- IRON Project. XLV. Ar XIII and Fe XXI
- Short Name:
- J/A+AS/147/253
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Breit-Pauli R-matrix method developed under the Iron Project has been used to obtain extensive sets of oscillator strengths and transition probabilities for dipole allowed and intercombination fine structure transitions in carbon like ions, Ar XIII and Fe XXI. The complete set consists of 1274 fine structure bound energy levels and 198259 oscillator strengths for Ar XIII, and 1611 bound levels and 300079 oscillator strengths for Fe XXI. These correspond to levels of total angular momenta of 0<=J<=7 of even and odd parities formed from total spin of 2S+1=5, 3, 1, and orbital angular momenta 0<=L<=9 with n<=10, 0<=l<=9 for each ion. The relativistic effects are included in the Breit-Pauli approximation. The close coupling wavefunction expansion for each ion is represented by the lowest 15 fine structure levels of target configurations, 2s^2^2p, 2s2p^2^ and 2p^3^. The energy levels are identified spectroscopically using a newly developed identification procedure. The procedure also makes a correspondence between the fine structure energy levels and LS terms. This provides the check for completeness of the calculated levels. Comparison is made of the present energies and the f-values with the available observed and theoretical values. Present transition probabilities agree very well with the relativistic atomic structure calculations of Mendoza et al. for the intercombination transitions, 2s2p^3^(^5^S{deg}_2_) - 2s^2^2p^2^(^3^P_1,2_,^1^D_2_). This further indicates that the importance of the neglected Breit interaction decreases with ion charge and constrains the uncertainty in the present calculations to within 15% even for the weak transitions.
- ID:
- ivo://CDS.VizieR/J/A+A/365/268
- Title:
- IRON Project. XLVII. Ni III
- Short Name:
- J/A+A/365/268
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper reports R-matrix calculations of electron impact excitation rates for Ni III. The calculation includes 70 LS terms corresponding to the configurations 3d^8^, 3d^7^4s, 3d^7^4p, and 3d^6^4s^2^. This expansion results in 162 fine structure levels and 13041 transitions, including optical, infrared, and ultraviolet lines. The collision strengths, including detailed resonance structures, were integrated over a Maxwellian distribution of electron energies and the resulting effective collision strengths are given for a wide range of temperatures. A collisional-radiative equilibrium model of the Ni III ion is constructed and the strongest lines in the optical and infrared spectral regions are identified. The emissivities of these lines and emissivity line ratio diagnostics are presented.
- ID:
- ivo://CDS.VizieR/J/A+AS/119/509
- Title:
- IRON Project. XVII. Radiative transition in Fe III
- Short Name:
- J/A+AS/119/509
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Table ls.dat contains all LS terms considered in this work and their energy values with complete designation. Table aij.dat contains f-, S-, and A-values of transitions, both in LS multiplet and in fine structure. For the full designation of the terms in the lower table check the top energy table. At the end of the lower table, a program in Fortran77 is written which can read the tables and calculate lifetime values from the A-values. Files ls.dat and aij.dat present transitions in Fe III (obs-file) among states that have been observed and the calculated energies were replaced by the observed energies to improve the accuracy (explained in the Ref). Files ls2.dat and aij2.dat (cal-file) contains transitions among the rest of the calculated energy states and all the transition energies are calculated ones. Hence the two files, one with observed energies (obs-file) and one with calculated energies (cal-file) are complement to each other with no common transitions. The uncertainties of the transition probabilities in cat-file, are expected to be higher than those in the obs-file as the observed energies are more accurate in general than the calculated ones. Total data: Septets: Number of bound energy terms = 54 Number of LS transitions = 40 (obs energies), 274 (cal energies) Number of fine structure transitions = 354 (obs energies), 3448 (cal energies) Quintets: Number of bound energy terms = 190 Number of LS transitions = 423 (obs energies), 3435 (cal energies) Number of fine structure transitions= 4756 (obs energies), 37042 (cal energies) Triplets: Number of bound energy terms = 359 Number of LS transitions = 712 (obs energies), 12885 (cal energies) Number of fine structure transitions= 4451 (obs energies), 80013 (cal energies) Singlets: Number of bound energy terms = 202 Number of LS transitions = 233 (obs energies), 3831 (cal energies) Number of fine structure transitions = 233 (obs energies), 3831 (cal energies) Total no of LS multiplets using observed energies = 1408 Total no of fjj values with observed energies = 9794 Total no of LS multiplets using calculated energies = 20425 Total no of fjj values with calculated energies = 124334 Total number of f-values using observed and calculated transition energies = 134,128
- ID:
- ivo://CDS.VizieR/J/A+AS/123/159
- Title:
- IRON Project. XXII. C and O radiative rates
- Short Name:
- J/A+AS/123/159
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The transition probabilities (s-1) within the ground configuration calculated in the present work for ions belonging to the carbon isoelectronic sequence are listed in Table 5, while those for ions belonging to the oxygen sequence are listed in Table 7. The first column in either table corresponds to the ion atomic number (Z), the second to the levels between which the transition occurs (Trans.), the third to the electric quadrupole transition probability (E2) and the last to the magnetic dipole transition probability (M1).
- ID:
- ivo://CDS.VizieR/J/A+AS/123/575
- Title:
- IRON Project XXIII. Fe XXII excitation rate
- Short Name:
- J/A+AS/123/575
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- New collision strengths have been calculated for 990 transitions among 45 fine structure n=2 and n=3 levels of Fe XXII. The relativistic Breit-Pauli formulation of the R-matrix method was employed in the close coupling approximation, with radiation damping of autoionizing resonances included for the first time in the calculations of excitation rate coefficients. It is found that, at low temperatures, the relativistic effects considerably enhance rate coefficients for the intercombination transitions, and the radiation damping effect reduces those for a few transitions. It is also found that resonances due to coupling with the n=3 levels significantly enhance rate coefficients for the transitions to low-lying levels at intermediate and high temperatures, and for the transitions to the n=2 high-lying levels at all temperatures. It is expected that the new data, tabulated at a wide range of temperatures, would lead to a revision of the spectral diagnostics of Fe XXII in laboratory and astrophysical sources, in particular the X-ray spectra observed from solar flares and tokamaks.
- ID:
- ivo://CDS.VizieR/J/A+AS/131/499
- Title:
- IRON Project XXIX. Boron isoelectronic sequence
- Short Name:
- J/A+AS/131/499
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- As part of the IRON Project, radiative rates have been calculated for the E1, E2 and M1 transitions within the n=2 complex in ions of the boron isoelectronic sequence (6<=Z<=28). The computations have been carried out with the atomic structure code SUPERSTRUCTURE which facilitates the generation of extended radiative datasets including configuration interaction, Breit-Pauli relativistic contributions and semi-empirical term-energy corrections. By means of extensive comparisons with the available datasets for this sequence, with detailed single-ion calculations and recent experiments, we have been able to assign accuracy ratings to the present A-values. We find that in general the spin-allowed and spin-forbidden E1 transitions are accurate to 10% and 20%, respectively, except for a few transitions in ions with Z<=7 that are perturbed by admixture with low-lying n=3 states (e.g. 2s^2^3l) and for those affected by the avoided crossing of the 2s2p^2^ ^2^S1/2 and ^2^P1/2 which takes place at Z~22. It is concluded that, statistically, the present dataset is the most accurate to date for this astrophysically relevant sequence.
