Relativistic Distorted-Wave Calculations of Electron Impact Excitation Cross Sections of Be-Like C ²⁺ Ions

A fully relativistic distorted-wave program is developed based on the Grasp92 and Ratip packages to calculate electron impact excitation (EIE) cross sections. As a first application of the program, the EIE cross sections of Be-like C ²⁺ ions from the metastable 1s²2s2p ³P to 1s²2p^{2 3}P excitation and the inner-shell excitations are calculated systematically. Meanwhile, the correlation effects of target states are discussed. It is found that the correlation effects play an important role in the low energy EIE cross sections. An excellent agreement is found when the results are compared with previous
calculations and recent measurements.