Branching Fractions and Oscillator Strengths for Fe II Transitions from the 3d 6( 5D)4p Subconfiguration

Bergeson, Scott; Mullman, K. L.; Wickliffe, W. E.; Lawler, J. E.; Litzén, Ulf; Johansson, S.

doi:10.1086/177391

Cited by 54 publications

(58 citation statements)

References 16 publications

(20 reference statements)

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“…This was done for more than half of the levels giving us a sufficient absolute wavelength calibration for all the laser dyes used. (24) [1] Bergeson et al (1996). * Lifetime taken from Schade et al (1988).…”

Section: Resultsmentioning

confidence: 99%

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Fe II lifetimes and transition probabilities

Schnabel

Schultz-Johanning

Kock

2004

A&A

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Abstract. Fe II radiative lifetimes were measured applying the time-resolved nonlinear laser-induced fluoresence technique. We investigated 21 levels of up to 47 000 cm −1 . The uncertainties are typically 2−3%. The lifetimes provide an improved absolute scale to our branching fractions which were measured with a Fourier transform spectrometer and a high-resolution grating spectrometer and which have been published earlier. We report absolute transition probabilities of 140 Fe II lines in the wavelength range 220-780 nm. The overall uncertainties are estimated to be 6% for the strong and up to 26% for the weak transitions. The results are compared with recent experimental data from the literature. Our large set of accurate data can be used for a reliability check of theoretical data calculated for iron abundances in astrophysical plasmas.

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Section: Resultsmentioning

confidence: 99%

“…The error bars of our data include statistical and estimated systematic uncertainties. (18) [1] Bergeson et al (1996). * Lifetime taken from Hannaford et al (1992).…”

Section: Resultsmentioning

confidence: 99%

Fe II lifetimes and transition probabilities

Schnabel

Schultz-Johanning

Kock

2004

A&A

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“…Moity (1983) had reported transition probabilities from laboratory arc measurements in the range 255 nm to 530 nm with typical uncertainties of greater than 20%. Bergeson et al (1996) reported accurate new laboratory measurements of transition probabilities for transitions between 224 nm and 276 nm having upper levels of the 3d 6 ( 5 D)4p subconfiguration in the range 38 000 cm −1 to 46 000 cm −1 , but they did not consider levels lying higher than 46 000 cm −1 . In general, there is a serious lack of accurate experimental transition probabilities for Fe II for transitions covering the UV to VUV (below 200 nm) spectral regions or from high lying energy levels.…”

Section: Introductionmentioning

confidence: 99%

The FERRUM project: Branching ratios and atomic transition probabilities of Fe II transitions from the 3d$\mathsf{^{6}}$(a$\mathsf{^{3}}$F)4p subconfiguration in the visible to VUV spectral region

Pickering

Johansson²,

Smith³

2001

A&A

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Abstract. We report measurements of the relative intensities of 81 emission lines of Fe II between 160 nm and 350 nm (62 168 cm −1 to 28 564 cm −1 ) from 4 levels by high resolution Fourier transform spectrometry, using a Penning discharge lamp as light source. These relative intensities have been used to determine the line branching fractions, which have then been combined with accurate experimental radiative lifetime measurements reported recently to give absolute transition probabilities and oscillator strengths for 81 lines. The accuracy of these f-values is compared with other previous experimental measurements, and with theoretical values. The new transition probabilities will allow accurate determinations of Fe II abundances in a wide variety of astrophysical objects.

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“…This implies that the uncertainty on the absolute metallicities is of the order of 30% but it is much smaller on the abundance ratios. Morton (1991); (b) Wiese et al (1996); (c) Welty et al (1999); (d) Bergeson & Lawler (1993b); (e) Biémont et al (1994); (f) Wiese et al (2001); (g) Bergeson & Lawler (1993a); (h) Bergeson et al (1994); (i) Bergeson et al (1996); (j) Fedchak et al (2000). .…”

Section: Metal Contentmentioning

confidence: 99%

Detection of molecular hydrogen in a near Solar-metallicity damped Lyman-α system at $z_\mathsf{abs}$ ≈ 2 toward Q 0551-366

Ledoux

Srianand²,

Petitjean

2002

A&A

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Abstract. We report the detection of H 2 , C , C  , C  and Cl  lines in a near Solar-metallicity ([Zn/H] = −0.13) damped Lyman-α (DLA) system at z abs = 1.962 observed on the line of sight to the quasar Q 0551−366. The iron-peak elements, X = Fe, Cr and Mn are depleted compared to zinc, [X/Zn] ∼ −0.8, probably because they are tied up onto dust grains. Among the three detected H 2 -bearing clouds, spanning 55 km s −1 in velocity space, we derive a total molecular hydrogen column density N(H 2 ) = 2.6 × 10 17 cm −2 and a mean molecular fraction f = 2N(H 2 )/(2N(H 2 ) + N(H )) = 1.7 × 10 −3 . The depletion of heavy elements (S, Si, Mg, Mn, Cr, Fe, Ni and Ti) in the central component is similar to that observed in the diffuse neutral gas of the Galactic halo. This depletion is approximately the same in the six C -detected components independently of the presence or absence of H 2 . The gas clouds in which H 2 is detected always have large densities, n H > 30 cm −3 , and low temperatures, T 01 < ∼ 100 K. This shows that presence of dust, high particle density and/or low temperature is required for molecules to be present. The photo-dissociation rate derived in the components where H 2 is detected suggests the existence of a local UV radiation field similar in strength to the one in the Galaxy. Star formation therefore probably occurs near these H 2 -bearing clouds.

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Branching Fractions and Oscillator Strengths for Fe II Transitions from the 3d 6( 5D)4p Subconfiguration

Cited by 54 publications

References 16 publications

Fe II lifetimes and transition probabilities

Fe II lifetimes and transition probabilities

The FERRUM project: Branching ratios and atomic transition probabilities of Fe II transitions from the 3d$\mathsf{^{6}}$(a$\mathsf{^{3}}$F)4p subconfiguration in the visible to VUV spectral region

Detection of molecular hydrogen in a near Solar-metallicity damped Lyman-α system at $z_\mathsf{abs}$ ≈ 2 toward Q 0551-366

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