Oscillator Strengths of Weak fe i Resonance Lines Measured by Combined Hook and Absorption Techniques

Huber, M. C. E.; Tubbs, Eldred F.

doi:10.1086/151761

Cited by 22 publications

(8 citation statements)

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“…of a strong resonance line having a reliable oscillator strength (and a large N f l ) with very weak lines (having a small N f l ) . Such measurements for Fe I [67] are in fact in agreement with the results of Blackwell et al [4], who needed relative measurements between at least six line pairs to cover the same dynamic range. The agreement suggests that the precision measures taken with the absorption technique alone [ 4 6 ] are not sabject to systematic errors.…”

Section: Combined Methods Leap-frogging and Bowtiessupporting

confidence: 89%

Transition Probabilities and Their Accuracy

Huber¹,

Sandeman²

1980

Phys. Scr.

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The classical methods for measuring transition probabilities, viz. the determination of lifetimes and branching ratios, and the absorption, hook, and emission techniques are briefly reviewed. The main advantages and difficulties of each method, as well as the accuracies reached, are described. Improved evaluation methods for hook spectrograms are summarized and the advances made with combinations of classical methods for determining and assessing oscillator strengths are described. The hitherto rarely exploited potential of magneto-rotation measurements for deriving accurate oscillator strengths and the promise of optogalvanic spectroscopy are mentioned. Applications of non-linear optical methods for f-value determinations are also discussed.

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Section: Combined Methods Leap-frogging and Bowtiessupporting

confidence: 89%

Transition Probabilities and Their Accuracy

Huber¹,

Sandeman²

1980

Phys. Scr.

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“…The present experiment was undertaken as a first step toward measuring absolute cross sections of the astrophysically im portant case of Fei^[ and other neutral elements of the iron group, with a combination of the hook method and absorption measurements (Huber & Tubbs 1972;Banfield, Huber, Parkinson & Tubbs 1973).…”

Section: Introductionmentioning

confidence: 99%

The spectrum of Cr I between 179.8 and 200 nm wavelengths, absorption cross sections, and oscillator strengths

1975

Proc. R. Soc. Lond. A

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The absorption spectrum of furnace-heated Cr vapour at wavelengths below 200 nm was recorded photoelectrically and by photography. By use of the hook method, the column density of neutral Cr atoms in the ground state was determined with the aid of the accurately known oscillator strengths of the resonance lines near 427 nm. The absorption cross section of the autoionized lines that dominate the ionization continuum could thus be obtained on an absolute scale. We also measured the wavelengths of many hitherto unreported lines near the ionization limit and derived a new value for the ionization potential, namely 54575.6 ± 0.3 cm -1 . Oscillator strengths for some of these lines are also given.

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“…The absorption measurements were reduced in a way similar to th a t described by Huber & Tubbs (1972). We read the equivalent widths from photoelectric tracings and corrected these observed values for the influence of the therm al line-emission stemming from the Cr-vapour in the furnace, and for the finite integration interval of the exit slit.…”

Section: E Xperim Ent and Data Reductionmentioning

confidence: 99%

“…Following a report on the chromium spectrum between 179.8 and 200 nm (Huber, Sandeman, & Tubbs 1975), which emphasized the photo-ionization cross-section, we describe here measurements of oscillator strengths of Cr 1 transitions, which were taken on Cr vapour in a high-temperature furnace. In order to cover a large dynamic range of line strengths, we used a combination of hook and absorption techniques (Huber & Tubbs 1972).…”

Section: Introductionmentioning

confidence: 99%

Oscillator strengths of Cr I lines lying between 200 and 541 nm from hook-method and absorption measurements in a furnace

Huber

Sandeman

1977

Proc. R. Soc. Lond. A

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Oscillator strengths of 148 transitions in the neutral chromium atom with wavelengths between 200 and 541 nm were determined in a high-temperature furnace by use of the hook and absorption methods for strong and weak lines, respectively. 114 of these gf -values are reported for the first time. Hook spectra taken at wavelengths near 430 nm assured accurate knowledge of the product of f -value and column density for prominent transitions with lower levels lying at 0 and ≈ 1 eV. The absolute scale is based on the best available oscillator strengths for the 427 nm resonance triplet. The relative scale matches measurements of the relative intensities of emission lines that correspond to transitions from a common upper level (z 5 P 0 2 ) to the ground level (a 7 S 3 ) as well as to excited terms (a 5 S, a 5 D). A slight adjustment (well within the calibration uncertainties) made our oscillator-strength scale agree with gf -values obtained by Cocke, Stark & Evans from beam-foil and branching-ratio measurements. Uncertainty estimates, given for each oscillator strength, are substantiated by the agreement (within error limits) of those f -values that could be measured by both, absorption and hook method.

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Oscillator Strengths of Weak fe i Resonance Lines Measured by Combined Hook and Absorption Techniques

Cited by 22 publications

References 0 publications

Transition Probabilities and Their Accuracy

Transition Probabilities and Their Accuracy

The spectrum of Cr I between 179.8 and 200 nm wavelengths, absorption cross sections, and oscillator strengths

Oscillator strengths of Cr I lines lying between 200 and 541 nm from hook-method and absorption measurements in a furnace

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