Regge pole representation of the limiting behavior of optically forbidden transitions in atoms and molecules Original Research Article

An appropriate choice for the complex angular momentum Regge poles in a dispersion relation representation of the electron differential cross sections in the momentum transfer squared, K2 at fixed impact energies, leads to reliable extrapolations of the generalized oscillator strengths for optically forbidden transitions down to the Lassettre limit at K2=0. The He 11S→21S, Ne 2p6(1S0)→2p5(2P1/2)3p and Xe 5p6(1S0)→5p5(2P3/2)5d[7/2] data at different impact energies are used to illustrate the applicability of the method to atoms. The method is also extended, with some success, to include molecular transitions SF6 S 2p(t1u)→A(t1u), C6H6 X̃1A1g→Ã1B1u and CH3COCH3 X̃1A1→Ã1A2. Comparison is made with other available results.