Electron impact excitation of Ni XX from its ground state

The R-matrix method is used to calculate electron impact excitation collision strengths in the F-like ion Ni XX from its 2 P o ground state. Configuration interaction wavefunctions are used to represent the sixteen LS-coupled target states which are retained in the R-matrix expansion. Effective collision strengths are then calculated for transitions from the fine-structure levels of the ground state to the fine-structure levels of a number of excited states for electron temperatures in the range (1-10)*10 6 K.