Electron impact excitation of the helium isoelectronic sequence

摘要

A simple analytic central potential with two adjustable parameters is proposed for the helium isoelectronic sequence. The potential parameters are obtained by appealing to the precise values of optical oscillator strengths calculated by Schiffetal. Using the Born approximation we calculate generalized oscillator strengths and integrated cross sections from threshold up to 5 keV for the electron impact excitation of the resonance transition 11Sndash;21Pin the helium isoelectronic sequence. The accuracy and the systematics of the results are discussed.