Electron impact ionisation of Li-like and Be-like carbon and nitrogen ions

Electron impact ionisation cross sections of the Li-like ions C IV and N V and the Be-like ions C III and N IV are calculated in a no-exchange Coulomb-Born approximation. Inner-shell ionisation is included but not autoionisation. Comparison with available theoretical and experimental data has been made. In C IV, the results agree with the recent calculations of Golden and Sampson (1977) and with exchange-classical impact-parameter calculations, which are about 30% higher than the crossed-beam experimental results of Crandall and co-workers (1978). In N V the results agree with those of Golden and Sampson but are now in close agreement with Crandall et. al.