J/ApJS/196/24 Electron-impact excitation of CrII (Wasson+, 2011)
Electron-impact excitation of Cr II: a theoretical calculation of effective
collision strengths for optically allowed transitions.
Wasson I.R., Ramsbottom C.A., Scott M.P.
<Astrophys. J. Suppl. Ser., 196, 24 (2011)>
=2011ApJS..196...24W 2011ApJS..196...24W
ADC_Keywords: Atomic physics
Keywords: atomic data - atomic processes - methods: numerical - plasmas -
scattering
Abstract:
In this paper, we present electron-impact excitation collision
strengths and Maxwellian averaged effective collision strengths for
the complicated iron-peak ion CrII. We consider specifically the
allowed lines for transitions from the 3d5 and 3d44s even parity
configuration states to the 3d44p odd parity configuration levels.
The parallel suite of R-Matrix packages, RMATRX II, which have
recently been extended to allow for the inclusion of relativistic
effects, were used to compute the collision cross sections. A total of
108 LSπ/280Jπ levels from the basis configurations 3d5,
3d44s, and 3d44p were included in the wavefunction representation
of the target including all doublet, quartet, and sextet terms.
Configuration interaction and correlation effects were carefully
considered by the inclusion of seven more configurations and a
pseudo-corrector {overline}4d type orbital. The 10 configurations
incorporated into the CrII model thus listed are 3d5, 3d44s,
3d44p, 3d34s2, 3d34p2, 3d34s4p, 3d4{overline}{4d},
3d34s{overline}{4d}, 3d34p{overline}{4d}, and 3d3{overline}{4d}2,
constituting the largest CrII target model considered to date in a
scattering calculation. The Maxwellian averaged effective collision
strengths are computed for a wide range of electron temperatures
2000-100000K which are astrophysically significant. Care has been
taken to ensure that the partial wave contributions to the collision
strengths for these allowed lines have converged with "top-up" from
the Burgess-Tully sum rule incorporated. Comparisons are made with the
results of Bautista et al. and significant differences are found for
some of the optically allowed lines considered.
Description:
The theoretical CrII model adopted in the present calculation has
been described in detail by Wasson et al. (2010, Cat. J/A+A/524/A35).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 40 280 Energy levels for all fine-structure target
states of CrII considered in the present work
table3.dat 69 8341 Theoretical oscillator strengths and transition
probabilities between all allowed fine structure
transitions of Cr II
table4.dat 169 8669 Maxwellian averaged effective collision strengths
against temperature for allowed fine structure
transitions of Cr II. Configurations are indexed
by Table 1.
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See also:
J/A+A/524/A35 : Effective collision strengths of CrII (Wasson+, 2010)
J/A+A/511/A68 : Transitions of CrII (Gurell+, 2010)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- Index [1,280] Index value
5- 17 A13 --- Config Configuration
19- 25 A7 --- LS LS state
27- 30 A4 --- J Level
32- 40 F9.7 Ry E Energy (in Rydbergs relative to the
3d5 6Se5/2 ground state)
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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- 3 I3 --- i [1,272] Lower level
5- 7 I3 --- j [75,274] Upper level
9- 12 A4 --- J(i) Lower level angular momentum
14- 17 A4 --- J(j) Upper level angular momentum
19- 25 F7.5 eV dE Energy difference between upper and lower levels
27- 36 E10.4 --- Flen Length oscillator strength
38- 47 E10.4 --- Fvel Velocity oscillator strength
49- 58 E10.4 --- Alen Length transition probability
60- 69 E10.4 --- Avel Velocity 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- 3 I3 --- i [1,272] Lower level
5- 7 I3 --- j [75,280] Upper level
9- 16 E8.2 --- ECS2k Effective collision strength at 2000K
18- 25 E8.2 --- ECS2.3k Effective collision strength at 2300K
27- 34 E8.2 --- ECS2.5k Effective collision strength at 2500K
36- 43 E8.2 --- ECS5k Effective collision strength at 5000K
45- 52 E8.2 --- ECS7.5k Effective collision strength at 7500K
54- 61 E8.2 --- ECS10k Effective collision strength at 10000K
63- 70 E8.2 --- ECS13k Effective collision strength at 13000K
72- 79 E8.2 --- ECS15k Effective collision strength at 15000K
81- 88 E8.2 --- ECS18k Effective collision strength at 18000K
90- 97 E8.2 --- ECS20k Effective collision strength at 20000K
99-106 E8.2 --- ECS30k Effective collision strength at 30000K
108-115 E8.2 --- ECS40k Effective collision strength at 40000K
117-124 E8.2 --- ECS50k Effective collision strength at 50000K
126-133 E8.2 --- ECS60k Effective collision strength at 60000K
135-142 E8.2 --- ECS70k Effective collision strength at 70000K
144-151 E8.2 --- ECS80k Effective collision strength at 80000K
153-160 E8.2 --- ECS90k Effective collision strength at 90000K
162-169 E8.2 --- ECS100k Effective collision strength at 100000K
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 16-Nov-2011