Stark widths and shifts for spectral lines of Sn IV

In this paper, we present theoretical Stark widths and shifts calculated corresponding to 66 spectral lines of Sn IV. We use the Griem semi-empirical approach and the COWAN computer code. For the intermediate coupling calculations, the standard method of least-squares fitting from experimental energy levels was used. Data are presented for an electron density of 1017 cm(-3) and temperatures T = 1.1-5.0 (10(4) K). The matrix elements used in these calculations have been determined from 34 configurations of Sn IV:4d(10)ns(n = 5-10), 4d(10)nd(n = 5-8), 4d(9)5s(2), 4d(9)5p(2), 4d(9)5s5d, 4d(8)5s5p(2) and 4d(10)5g for even parity and 4d(10)np(n = 5-8), 4d(10)nf (n = 4-6), 4d(9)5snp(n = 5-8), 4d(8)5s(2)5p and 4d(9)5snf (n = 4-10) for odd parity. Also, in order to test thematrix elements used in our calculations, we present calculated values of radiative lifetimes of 14 levels of Sn IV. There is good agreement between our calculations and the experimental radiative lifetimes obtained from the bibliography. The spectral lines of Sn IV are observed in UV spectra of HD 149499 B obtained with the Far Ultraviolet Spectroscopic Explorer, the Goddard High Resolution Spectrograph and the International Ultraviolet Explorer. Theoretical trends of the Stark broadening parameter versus the temperature for relevant lines are presented. Also our values of Stark broadening parameters have been compared with the data available in the bibliography.