Forbidden and allowed transitions among the first seven levels in sodium-like Ni XVIII due to electron impact

The R-matrix method is used to calculate electron collision strengths for the forbidden and allowed transitions among the seven lowest states of Ni XVIII. Configuration interaction wave-functions are used to represent the target states. The standard and no-exchange R-matrix codes have been used to calculate the contribution of partial waves with L≤9 and L>9 respectively. Collision strengths are tabulated at selected energies in the range 45-120 Ryd for all 21 transitions among the lowest seven target states. Effective collision strengths are tabulated for electron temperature in the range log Te=4.00 to log Te=6.00 K. This is the first detailed calculation on this ion in which the effects of exchange, channel couplings and short-range correlation effects are taken into account. (orig.)