ASTROPHYSICAL DETERMINATION OF OPTICAL OSCILLATOR-STRENGTHS FOR TI II

An internally consistent set of relative oscillator strengths for 109 spectral lines of Ti II in the range 3800-5500 angstrom has been deriv ed. These oscillator strengths have been obtained by combining availab le laboratory data and theoretical calculations with new astrophysical oscillator strengths determined from both published photo-graphic equ ivalent width lists and spectral synthesis of a number of available Re ticon spectra of several sharp-lined stars. The accuracy of our astrop hysical oscillator strengths has been tested by determining astrophysi cal gf-values for a number of lines of Fe II by the same methods. The Ti II data have been normalized to the astrophysical oscillator streng ths of Kostyk & Orlova, which also places them essentially on the scal e of Danzmann & Kock, one of the most recent and extensive experimenta l data sets. It appears that the accuracy of the relative gf-values in our final mean list for Ti II is typically about 0.08 dex. The absolu te normalization is believed to be secure to within about 0.15 dex.