Inelastic neutral atom scattering

Scattering of electrons, fast atoms, or ions with laser-excited atoms A can result in elastic, inelastic, or superelastic collisions. In the latter case, the excitation energy of A is partly converted into kinetic energy of the scattered particles. Orientation of the excited atoms by optical pumping with polarized lasers allows investigations of the influence of the atomic orientation on the differential cross sections for A -f-B collisions, which differs for collisions with electrons or ions from the case of neutral atoms [13.124]. An example of the measurement of differential cross sections of the reactive collisions Na - -HF is given in [13.125]. 

The scope of this chapter will be on these recent developments of the last three years, 1971 to 1973. We restrict ourselves to the interaction of neutral partners, with no restriction to the energy or state of the species. The article starts with a brief review of basic scattering laws and experimental techniques used in the experiments (Section II). Then the theory of elastic scattering is reviewed, the different cross section features are summarized and their sensitivity to the potential is discussed. Perturbations of these results caused from anisotropic potentials, inelasticities or potential crossings are described (Section 111). The next Section IV contains a survey of methods of how to determine the potential from the data. The emphasis will be on the inversion procedures. Finally, the results are summarized in Section V where, besides the atom-atom interactions in the ground states, new results for metastable species and molecules are included. 

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