Theoretical study of the Stark broadening for Mg iv spectral lines of astrophysical interest

Abstract

Emission lines of Mg IV have been detected in the Far Ultraviolet Spectroscopic Explorer (FUSE) spectrum of LS V +46 • 21 star and in the Space Telescope Imaging Spectrograph (STIS) spectrum of BD +28 • 4211 star. This fact justifies our interest in providing spectroscopic parameters of Mg IV. Stark broadening parameters for 169 spectral lines of Mg IV have been calculated by using the Griem semi-empirical approach. The matrix elements used in these calculations has been determined from 13 configurations of Mg IV: 2s 1 2p 6 , 2s 2 2p 4 ns (n = 3-5), 2s 2 2p 4 nd (n = 3-5) and 2s 2 2p 4 5g for even parity and 2s 2 2p 5 , 2s 2 2p 4 np (n = 3, 4) and 2s 2 2p 4 nf (n = 4, 5) for odd parity. Our calculations were made by using the Cowan code. Data are presented for an electron density of 10 17 cm −3 and temperatures T = 1.0-10.0 (10 4 K). Also we present calculated values of transition probabilities for 30 spectral lines and radiative lifetimes corresponding to its upper levels. These values were analysed using the data found in the literature. Theoretical trends of the Stark broadening parameters versus the temperature for several lines of astrophysical interest are presented.