HYPERFINE STRUCTURE AND ISOTOPE SHIFT IN Tl II WITH ASTROPHYSICAL APPLICATIONS

摘要

Fourier transform (FT) spectra of Tl II with resolved hyperfine structure (hfs) have been analyzed in the region 1790-3400 A. Measured isotope shifts (IS) for two transitions, including the ~1S-~3P inter-combination line to the ground state at 1908.6 A, are reported. Accurate Ritz wavelengths for isotope and hyperfine components of the ~1S-~1P resonance line at 1321.6 A are given. The accuracy is better than 0.3 mA for measured wavelengths and better than 0.4 mA for the Ritz wavelengths. Theoretical multi-configuration Dirac-Fock (MCDF) calculations, including core polarization, show that the LS-allowed 1321.6 A transition is a factor of 30 stronger than the intercombination line at 1908.6 A. The application of the new Tl II data to astrophysical spectra obtained with the Hubble Space Telescope is discussed.