Generalized oscillator strengths for the 3s2S→3p2P transition in Mg ii

Generalized oscillator strengths (GOS’s) are calculated from accurate five-state close-coupling differential cross sections for the resonance transition in Mg i i at electron impact energies 15, 50, 60, and 100 eV. Curves of the GOS versus momentum transfer squared, $K^2$, remain separate down to zero scattering angle, with the 50, 60, and 100 eV curves showing maxima close to $K^2$=0. We interpret the new phenomenon, maxima at small scattering angles, as a manifestation of the inadequacy of the Lassettre et al. formula to represent the GOS at small $K^2$ for intermediate energies. At 50 eV our GOS’s compare well with those deduced from measurement.