Breit-Pauli R-matrix calculation of fine-structure effective collision strengths for the electron impact excitation of Mg?V

摘要

Context. Electron-impact excitation collision strengths are required for the analysis and interpretation of stellar observations. Aims. This calculation aims to provide effective collision strengths for the Mg Vion for a larger number of transitions and for a greater temperature range than previously available, using collision strength data that include contributions from resonances. Methods. A 19-state Breit-Pauli R-matrix calculation was performed. The target states are represented by configuration interaction wavefunctions and consist of the 19lowest LSstates, having configurations 2s22p4, 2s2p5, 2p6, 2s22p33s, and 2s22p33p. These target states give rise to 37fine-structure levels and 666possible transitions. The effective collision strengths were calculated by averaging the electron collision strengths over a Maxwellian distribution of electron velocities. Results. The non-zero effective collision strengths for transitions between the fine-structure levels are given for electron temperatures()in the range .Data for transitions among the 5fine-structure levels arising from the 2s22p4 ground state configurations, seen in the UVrange, are discussed in the paper, along with transitions in the EUVrange - transitions from the ground state 3Plevels to 2s2p53Plevels. The 2s22p41D-2s2p51Ptransition is also noted. Data for the remaining transitions are available at the CDS. Key words: atomic processes - line: formation - methods: analytical