Integral cross section with magnetic sublevels and polarization degree of He-like Cl ions by electron impact

The Breit-Pauli R-matrix method with 17 fine-structure levels is used to calculate integral cross sections with magnetic sublevels for electron-impact excitation of He-like Cl ions from the ground state. The integral cross sections are obtained for transitions from the ground state to the fine-structure levels of all the excited states of the $1s2l$ $(l=0,1)$ configurations. Polarization degrees for the w (1s²0.2em0ex¹S₀-1s2p0.2em0ex¹P₁), y (1s²0.2em0ex¹S₀-1s2p0.2em0ex³P₁), and x (1s²0.2em0ex¹S₀-1s2p0.2em0ex³P₂) lines of low and moderately charged He-like ions are also obtained for a systematic investigation of the atomic number dependence. Our results for the polarization degree of He-like Cl ions are found to be in excellent agreement with experimental and other theoretical results.