Electronpositiveion scattering near reaction thresholds: Effect of longrange polarization forces
Abstract
A multichannel version of effectiverange theory is developed, applicable to electron scattering by positive ions. The formalism allows for the inclusion of the effect of longrange inversepowerlaw interactions arising from target distortion in the field of the projectile. A perturbation theory is described for the construction of asymptotic states accounting for the combined effect of Coulomb and polarization forces. The explicit extraction of threshold branchpoint singularities leaves modified reactionmatrix elements that vary slowly with energy, thereby permitting the smooth extrapolation of scattering parameters through reaction thresholds. A systematic procedure is made available to determine the effect of longrange forces on quantum defects and resonance level shifts; it is applied here, as an illustration, in first order. The theory provides an extension, to a wider class of scattering systems and longrange interactions, of an analysis of threshold behavior in electronion reactions given some time ago [M. Gailitis, Sov. Phys. JETP 17, 1328 (1963)].
 Publication:

Physical Review A
 Pub Date:
 October 1998
 DOI:
 10.1103/PhysRevA.58.2864
 Bibcode:
 1998PhRvA..58.2864R
 Keywords:

 34.80.Kw;
 03.65.Nk;
 34.10.+x;
 Electronion scattering;
 excitation and ionization;
 Scattering theory;
 General theories and models of atomic and molecular collisions and interactions