THEOREM ON SEPARATION OF COUPLED DIFFERENTIAL EQUATIONS, RESONANCE EFFECTS AND THRESHOLD BEHAVIOUR

The aim of this work is to show the importance of the theorem on the separation of coupled dierential equations in elastic scattering when the electron energy is below the threshold necessary to produce excitation of the state 1 from the ground state 0. We apply a schematical model to study the resonance eects in electron-hydrogen scattering. We are concerned with the behaviour of various cross-sections in the neighbourhood of the threshold of a new mode of scattering in which the electron possesses any quantized angular momentum, and examine the eects of the change in the centrifugal potentials in the case 1s-2s-2p close-coupling approximation. We conclude by discussing the threshold behaviour and its relation to resonance eects. PACS numbers: 34.80.Bm UDC 539.18