J/A+A/541/A61 Oscillator and collision strengths for SiVIII (Tayal+, 2012)
Breit-Pauli oscillator strengths and electron excitation collision strengths
for Si VIII.
Tayal S.S.
<Astron. Astrophys. 541, A61 (2012)>
=2012A&A...541A..61T 2012A&A...541A..61T
ADC_Keywords: Atomic physics
Keywords: atomic data - atomic processes - line formation
Abstract:
Oscillator strengths and electron impact excitation collision
strengths for transitions between the 68 fine-structure levels of the
2s22p3, 2s2p4, 2p5, 2s22p23s, 2s22p23p, 2s22p23d
and 2s2p33s configurations in SiVIII are calculated. Thermally
averaged collision strengths are presented as a function of electron
temperature for application to solar and other astrophysical plasmas.
Description:
The collision strengths have been calculated using the
B-spline Breit-Pauli R-matrix method for allowed and forbidden
transitions in SiVIII. The relativistic effects have been incorporated
through mass, Darwin and spin-orbit one-body operators in the
Breit-Pauli Hamiltonian in the scattering calculation, while in the
calculation of oscillator strengths the one-body and two-body
relativistic operators are included. Flexible non-orthogonal sets of
spectroscopic and correlation radial functions are used to obtain
accurate description of SiVIII levels and to represent the scattering
functions. The 68 fine-structure levels of the 2s22p3, 2s2p4,
2p5, 2s22p23s, 2s22p23p, 2s22p23d and 2s2p33s
configurations have been considered in both the radiative and
scattering calculations. The present scattering calculations are more
extensive than previous ones, leading to a total 2278 transitions
between fine-structure levels.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 67 68 Excitation energies (in Ryd) of the 68 target
levels included in the present transition rates
and scattering calculations
table2.dat 96 45 Comparison of oscillator strengths and transition
probabilities for some dipole radiative E1
transitions
table3.dat 98 654 Oscillator strengths and transition probabilities
for dipole radiative E1 transitions
table4.dat 117 2278 Effective collision strengths for transitions
in SiVIII
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See also:
J/ApJ/526/544 : Collision strengths in S III (Tayal+, 1999)
J/ApJS/123/295 : Electron impact excitation in Fe XI (Gupta+, 1999)
J/A+A/418/363 : Effective collision strengths for Cl II (Tayal+, 2004)
J/A+A/426/717 : Oscillator strengths for ClII lines (Tayal+, 2004)
J/A+A/486/629 : Effective collision strengths for C II (Tayal, 2008)
J/ApJS/163/207 : Oscillator and collision strengths in NI (Tayal+, 2006)
J/ApJS/166/634 : OIV Effective collision strength (Tayal+, 2006)
J/A+A/510/A79 : Effective collision strengths for K II (Tayal+, 2010)
J/ApJS/188/32 : Breit-Pauli transition probabilities for SII (Tayal+, 2010)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- Index [1,68] Index
4- 29 A26 --- State State
31 I1 --- 2J J value for the level of the state
33- 40 F8.5 Ry E Present excitation energy
42- 50 F9.6 Ry EBL Excitation energy from CI calculation of
Bhatia & Landi, (2003, At. Data and Nucl.
Data Tables, 85, 317)
52- 59 F8.5 Ry Eexp ? Excitation energy from experiment (1)
61- 67 E7.3 ns tau ? Lifetime in dipole approximation from
the present calculation
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Note (1): From NIST compilation (http://physics.nist.gov)
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 18 A18 --- i Initial level of a transition
20 A1 ---- --- [-]
22- 44 A23 --- f Final level of a transition
46 I1 ---- gi (2J+1) value for initial level of a transition
48 I1 ---- gf (2J+1) value for final level of a transition
50- 57 E8.3 --- fif Present length value of oscillator strength
59- 67 E9.3 s-1 Aif Present length value of transition probability
69- 76 E8.3 --- fifBL Length value of oscillator strength from
calculations of Bhatia & Landi,
(2003, At. Data and Nucl. Data Tables, 85, 317)
78- 86 E9.3 s-1 AifBL Length value of transition probability from
calculations of Bhatia & Landi,
(2003, At. Data and Nucl. Data Tables, 85, 317)
88- 96 E9.3 s-1 AifTF Length value of transition probability from
calculations of Tachiev & Froese Fischer
(2002, Cat. J/A+A/385/716)
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 26 A26 --- i Initial level of a transition
28 A1 ---- --- [-]
30- 55 A26 --- f Final level of a transition
57 I1 --- gi (2J+1) value for the lower level of the
transition
59- 60 I2 --- gf (2J+1) value for the upper level of the
transition
62- 70 F9.3 0.1nm lambda Wavelength of the transition
72- 80 E9.4 --- fL Present length value of oscillator strength
81- 89 E9.4 --- fV Present velocity value of oscillator strength
90- 98 E9.4 s-1 Aif Present length value of transition probability
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- i [1,67] i lower level index of the transition
3 A1 ---- --- [-]
4- 5 I2 --- j [2,68] j upper level index of the transition
7- 13 E7.3 --- ECS1 Effective collision strength at Te=10000K
15- 21 E7.3 --- ECS2.5 Effective collision strength at Te=25000K
23- 29 E7.3 --- ECS5 Effective collision strength at Te=50000K
31- 37 E7.3 --- ECS7.5 Effective collision strength at Te=75000K
39- 45 E7.3 --- ECS10 Effective collision strength at Te=100000K
47- 53 E7.3 --- ECS20 Effective collision strength at Te=200000K
55- 61 E7.3 --- ECS40 Effective collision strength at Te=400000K
63- 69 E7.3 --- ECS60 Effective collision strength at Te=600000K
71- 77 E7.3 --- ECS80 Effective collision strength at Te=800000K
79- 85 E7.3 --- ECS100 Effective collision strength at Te=1000000K
87- 93 E7.3 --- ECS120 Effective collision strength at Te=1200000K
95-101 E7.3 --- ECS200 Effective collision strength at Te=2000000K
103-109 E7.3 --- ECS300 Effective collision strength at Te=3000000K
111-117 E7.3 --- ECS400 Effective collision strength at Te=4000000K
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Acknowledgements:
Swaraj Tayal, stayal(at)cau.edu
(End) Patricia Vannier [CDS] 02-Apr-2012