The O iv and S iv intercombination lines in the ultraviolet spectra of astrophysical sources     

F. P. Keenan  S. Ahmed  T. Brage  J. G. Doyle  B. R. Espey  K. M. Exter  A. Hibbert  M. T. C. Keenan  M. S. Madjarska  M. Mathioudakis  D. L. Pollacco 《Monthly notices of the Royal Astronomical Society》2002,337(3):901-909

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Diel variations in iron speciation in northern Australian shelf waters     

T. D. Waite  R. Szymczak  Q. I. Espey  M. J. Furnas 《Marine Chemistry》1995,50(1-4)

Iron in northern Australian shelf waters was found predominantly in fine (< 0.2 μm) 8-hydroxyquinoline-reactive form or in larger (1.0 μm) particulate form. Partitioning into the larger size fraction dominated during a period of high turbidity following a cyclonic resuspension event. Only a small component of the iron pool reacts rapidly with the strong ferrous binding agent ferrozine. The concentration of the ferrozine-reactive component is strongly dependent on light intensity with maximum concentration observed at peak light intensity. The close correlation between ferrozine-reactive iron concentration and light intensity suggests a fine balance between Fe(III) reduction and Fe(II) oxidation with the steady state concentration observed being strongly influenced by light induced changes in redox kinetics. An observed lack of association between particulate iron concentrations and the concentration of ferrozine-reactive iron suggests that the soluble rather than the particulate iron pool is most influenced by light. The chromophore may be an Fe(III)-organic complex with the strong iron binding ligand that is now recognised to be present in seawater.  相似文献   

[Al ii] in the ultraviolet spectrum of the symbiotic star RR Telescopii     

F. P. Keenan  B. R. Espey  M. Mathioudakis  K. M. Aggarwal  F. L. Crawford  W. A. Feibelman  F. C. McKenna 《Monthly notices of the Royal Astronomical Society》1999,309(1):195-198

An inspection of a GHRS/ HST spectrum of the symbiotic star RR Telescopii reveals the presence of the [Al  ii ] 3s²¹S – 3s3p ³P₂ line at a vacuum wavelength of 2661.06±0.08 Å, 8.89±0.08 Å away from the Al  ii ] 3s²¹S – 3s3p ³P₁ intercombination transition at 2669.95 Å, in good agreement with the theoretical prediction of Δ λ =8.80 Å. We also find that the Al  ii ] line profile is asymmetric, showing a strong low-density component with a weak high-density wing, redshifted by 30 km s⁻¹, in agreement with the findings of Schild & Schmid, which were based on optical observations. Our measurement of the emission-line ratio R I (2661.06 Å)/ I (2669.95 Å)=0.027±0.003 implies log  N _e=5.8±0.2, in good agreement with the densities found from other ions, such as Si  iii . These results provide strong evidence that we have detected the [Al  ii ] line, the first time (to our knowledge) that this feature has been reliably identified in an astrophysical or laboratory spectrum.  相似文献   

Emission lines of [Ne IV] in the optical and ultraviolet spectra of gaseous nebulae     

Keenan  Aller  Bell  Espey  Feibelman  Hyung  McKenna  & Ramsbottom 《Monthly notices of the Royal Astronomical Society》1998,295(3):683-690

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