- ID:
- ivo://CDS.VizieR/J/A+A/408/789
- Title:
- Iron Project. LIII. Fe XVII
- Short Name:
- J/A+A/408/789
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- An extensive set of fine structure levels and corresponding transition probabilities for allowed and forbidden transitions in Fe XVII is presented. A total of 490 bound energy levels of Fe XVII of total angular momenta 0<=J<=7 of even and odd parities with 2<=n<=10, 0<=l<=8, 0<=L<=8, and singlet and triplet multiplicities, are obtained. They translate to over 2.6x10^4^ allowed (E1) transitions that are of dipole and intercombination type, and 2312 forbidden transitions that include electric quadrupole (E2), magnetic dipole (M1), electric octopole (E3), and magnetic quadrupole (M2) type representing the most detailed calculations to date for the ion. Oscillator strengths f, line strengths S, and coefficients A of spontaneous emission for the E1 type transitions are obtained in the relativistic Breit-Pauli R-matrix approximation. A-values for the forbidden transitions are obtained from atomic structure calculations using codes SUPERSTRUCTURE and GRASP. The energy levels are identified in spectroscopic notation with the help of a newly developed level identification algorithm. Nearly all 52 spectroscopically observed levels have been identified, their binding energies agreeing within 1% with our calculation. Computed transition probabilities are compared with other calculations and measurement. The effect of 2-body magnetic terms and other interactions is discussed. The present data set enhances by more than an order of magnitude the heretofore available data for transition probabilities of Fe XVII.
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- ID:
- ivo://CDS.VizieR/J/A+A/413/779
- Title:
- Iron Project. LIV. Fe XX
- Short Name:
- J/A+A/413/779
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- An extensive set of oscillator strengths (f), line strengths (S) and radiative decay rates (A) for dipole allowed, intercombination and forbidden transitions in Fe XX is presented. Results include 1792 bound fine structure levels of total angular momenta J=1/2-19/2 of even and odd parities, with 2<=n<=10, 0<=l<=14, orbital angular momenta, 0<=L<=14, and total spin multiplicities 2S+1=2,4,6, yielding to about 3.8x10^5^ allowed and 13,874 forbidden transitions in Fe XX. These results far exceed the available data in literature. The existing data compiled by the National Institute for Standards and Technology (NIST) are available for little over one hundred transitions, and the previously calculated data under the Opacity Project includes 75 590 LS multiplets. The present ab initio calculations are carried out in the close coupling approximation using the relativistic Breit-Pauli R-matrix method for allowed and intercombination E1 transitions. The wavefunction expansion includes 20 fine structure levels of configurations 2s ^2^2p^2^, 2s2p^3^, and 2p^4^ of the core ion Fe XXI. Computed energy levels are identified spectroscopically using a newly developed procedure based on quantum defects and channel contributions. All 55 observed levels have been identified and are in agreement to much less than 1% with most of the calculated values. Coefficients for radiative decays for the forbidden E2, E3, M1 transitions are obtained through atomic structure calculations including relativistic terms in the Breit-Pauli approximation using the code SUPERSTRUCTURE. The theoretical transition probabilities are compared with available values, with varying degree of agreement.
- ID:
- ivo://CDS.VizieR/J/A+A/448/779
- Title:
- IRON Project. LXI. Fe IV radiative transitions
- Short Name:
- J/A+A/448/779
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Radiative decay rates (A) and line strengths (S) are presented for a large number of electric dipole allowed (E1) and forbidden electric quadrupole (E2), octupole (E3) and magnetic dipole (M1) transitions in Fe IV. The ion is amongst the most complex iron ions and exhibits effects of strong electron correlation. It has closely spaced fine structure levels from seven configurations: 3s^2^3p^6^3d^5^, 3s^2^3p^6^3d^4^4s, 3s^2^3p^6^3d^4^4p, 3s^2^3p^6^3d^4^4d, 3s^2^3p^6^3d^3^4s4p, 3s^2^3p^6^3d^3^4s4d, 3s^2^3p^5^3d^6^ before an energy gap could be noted. Atomic parameters are presented for multipole radiative transitions among the 1275 fine structure levels dominated by these seven configurations. A total of approximately 173000 transitions of type E1, E2, E3 and M1 are presented.
- ID:
- ivo://CDS.VizieR/J/A+A/457/721
- Title:
- IRON Project. LXII. Fe XVIII transitions
- Short Name:
- J/A+A/457/721
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- An extensive set of oscillator strengths (f), line strengths (S) and radiative decay rates (A) for the allowed and forbidden transitions in Fe XVIII is presented. The results include 1174 fine structure levels of total angular momenta J=1/2-17/2 of even and odd parities with 2<=n<=10, 0<=l<=9, orbital angular momenta, 0<=L<=11, and spin multiplicities 2, 4. These yield about 171500 transitions. The allowed electric dipole (E1) transitions, 141 869 in total, are obtained in the close coupling approximation using the relativistic Breit-Pauli R-matrix (BPRM) method. The forbidden electric quadrupole (E2), octupole (E3), and magnetic dipole (M1), quadrupole (M2) transitions, 29 682 in total, are obtained from configuration interaction Breit-Pauli atomic structure calculations using the code SUPERSTRUCTURE. The close coupling wavefunction expansion for Fe XVIII includes 10 levels of configurations 2s^2^ 2p^4^, 2s2p^5^, and 2p^6^ in the BRPM calculations. All fine structure levels have been identified spectroscopically.
365. IRON project LXIV
- ID:
- ivo://CDS.VizieR/J/A+A/469/1203
- Title:
- IRON project LXIV
- Short Name:
- J/A+A/469/1203
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This work reports radiative transition rates and electron impact excitation rate coefficients for levels of the n=3, 4, 5, 6, 7, 8 configurations of CaII. The radiative data were computed using the Thomas-Fermi-Dirac central potential method in the frozen core approximation and includes the polarization interaction between the valence electron and the core using a model potential. This method allows for configuration interactions (CI) and relativistic effects in the Breit-Pauli formalism. Collision strengths in LS-coupling were calculated in the close coupling approximation with the R-matrix method. Then, fine structure collision strengths were obtained by means of the intermediate-coupling frame transformation (ICFT) method which accounts for spin-orbit coupling effects.
366. IRON project. LXVIII
- ID:
- ivo://CDS.VizieR/J/A+A/514/A40
- Title:
- IRON project. LXVIII
- Short Name:
- J/A+A/514/A40
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A new R-matrix scattering calculation for electron collisional excitation of Fe XI is presented and compared to earlier calculations. The calculation includes 145 LS terms and 465 fine-structure levels and uses the intermediate-coupling frame transformation method (ICFT). We discuss the strong interactions that exist between three J=1 levels in the 3s2 3p3 3d electron configuration. These levels give rise to strong lines in the EUV spectrum and their energies and identifications have been the source of much confusion in the literature. We show that the oscillator and collision strengths linking these levels to the ground levels of the ion are very sensitive to the choice of configuration basis and argue that most earlier calculations have failed to represent these levels adequately.
- ID:
- ivo://CDS.VizieR/J/A+A/293/953
- Title:
- IRON project VI. FeII collision strengths
- Short Name:
- J/A+A/293/953
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- (no description available)
- ID:
- ivo://CDS.VizieR/J/A+A/293/967
- Title:
- IRON Project VII. FeII radiative transitions
- Short Name:
- J/A+A/293/967
- 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 aij.dat table check the energy table in ls.dat. A program in Fortran77, prog.f , can read the table in aji.dat and calculate lifetime in seconds from the A-values. The ls.dat and aij.dat present transitions in Fe II (obs-file) among states that have been observed and the calculated energies were replaced by the observed energies to improve the accuracy. The ls2.dat and aij2.dat files (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-files, are expected to be higher than those in the obs-file as the observed energies are more accurate in general than the calculated ones. The transition energy, EDIFF, in cal-file is written by one more significant digit compared to the obs-file with observed energies. Total data: Number of bound states: Total number of octet bound states below threshold (lmx= 7) = 6 Total number of sextet bound states below threshold (lmx= 9) = 205 Total number of quartet bound states below threshold (lmx= 7)= 308 Total number of doublet bound states below threshold (lmx= 7)= 226 Net Total = 745 Total no of LS multiplets using observed energies = 3109 Total no of fjj values with observed energies = 21,589 Total no of LS multiplets using calculated energies = 16164 Total no of fjj values with calculated energies = 136330 Total number of f-values using observed and calculated transition energies = 157,919
- ID:
- ivo://CDS.VizieR/J/A+AS/109/193
- Title:
- IRON project VIII. Ti-like ions
- Short Name:
- J/A+AS/109/193
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- (no description available)
- ID:
- ivo://CDS.VizieR/J/A+AS/108/1
- Title:
- IRON Project. V. O-like ions
- Short Name:
- J/A+AS/108/1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- (no description available)
