Lifetimes and Oscillator Strengths for Ultraviolet Transitions in Neutral Sulfur

Abstract

A consistent set of f-values for vacuum ultraviolet lines of S I is deduced from a combination of laser lifetime measurements and theoretical branching ratios. The new results are compared with results deduced from absorption by interstellar gas toward f Ophiuchi, and good agreement is observed for most transitions.

Calculated f-values for LS-allowed and Semi-Forbidden Intersystem Lines of Neutral Sulphur

“…Unlike the situation for the 3d 3 D o J transitions our results for 4d 3 D o J agree rather well with the experimental results given by Morton [11] and also the observational determinations of Federman and Cardelli [2]. Our f -values for these 4d lines are also in good agreement with the recent relativistic Hartree-Fock calculation of Bie¨mont et al [12].…”

“…Experiment [11,13,14] obtains f -values for the 5d 3 D o J transitions which are much larger than our calculated values, the observed values of Federman and Cardelli [2] and the calculated values of Bie¨mont et al [12]. This is also the case for the 6d 3 D o J transitions although the results of Federman and Cardelli [2] and Bie¨mont et al [12] are exceptionally low for the J 1 line, even compared to our own results.…”

“…In Table III we show our preliminary results for the allowed E1 transitions performed in an intermediate coupling approximation with theoretical energies adjusted to experiment, and we compare these with others from theory (Tayal [10] and Chen and Msezane [8]), experiment (Morton [11]), a combination of the two (Bie¨mont et al [12]) and observation (Federman and Cardelli [2]). The two purely theoretical approaches of Tayal [10] and Chen and [10] and Chen and Msezane [8]) as for the LS coupling results in Table II. The oscillator strengths given by Morton [11] were taken from experimental determinations compiled by Wiese and co-workers [13,14].…”

“…During the``6th International Colloquium on Atomic Spectra and Oscillator Strengths'' we became aware of a further theoretical calculation of oscillator strengths for lines in neutral sulphur (Bie¨mont et al [12]). This method used a relativistic Hartree-Fock approach to calculate the f -values; they do not give results for any of the 4s or 3d transitions.…”

Characterization of the Far‐ultraviolet Spectrum of Pt/Cr‐Ne Hollow Cathode Lamps as Used on the Space Telescope Imaging Spectrograph on Board the Hubble Space Telescope

“…The region between 1430 and 1500 8, which will benefit most from the availability of the Cr lines for calibration purposes, contains a number of lines of astrophysical interest. Most notable are the S i lines, which have a number of applications ranging from chromospheric emission from latetype giants (Judge 1988) to studies of the ISM (Federman & Cardelli 1995;Biémont et al 1998) to comets (Feldman et al 1991) and the volcanos of Io (Feaga et al 2002).…”