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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
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:
FileName Lrecl Records Explanations
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.
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
Bytes Format Units Label Explanations
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)
Byte-by-byte Description of file: table3.dat
Bytes Format Units Label Explanations
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
Byte-by-byte Description of file: table4.dat
Bytes Format Units Label Explanations
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
History: From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 16-Nov-2011
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