Excitation of Ca+by electron impact: polarization of line radiation and transitions between fine-structure levels

R matrices calculated by Burke and Moores (1968) for electron impact excitation of the 3d 2 D and 4p 2 P levels in Ca + are used. Collision strengths for excitation of fine-structure levels are obtained at energies below and above the threshold for excitation of 4p 2 P. These collision strengths are of interest in astrophysics. The polarization of radiation emitted from 2 P is related to the cross sections for excitation of the 2 P components. Calculated values for these cross sections and for the polarization of the 2 P- 2 S multiplet are given for a range of excitation energies.