β Scribed by R.D Peccei; R.D Viollier
No coin nor oath required. For personal study only.
We study the analyticity properties of forward electron-neutral atom scattering in a second quantized formalism. We derive a Low equation for these processes and deduce from it the location of direct and exchange bound state poles and the presence of both right-and left-hand cuts. We also examine the singularities produced by the exchange Born terms in a potential approximation and identify their physical origin. In a local theory, these Born term singularities are a result of the exchange of ionized atoms accompanied by a photon. Based on the singularity structure that we have obtained, we derive novel dispersion relations for forward electron-atom scattering. These equations contain additional terms not present in the "customary" form of dispersion relations for atomic scattering found in the literature. We comment on, and critically discuss, recent work done in this area. The possibility of anomalous thresholds is examined and they are seen to be irrelevant for these processes.
π SIMILAR VOLUMES
Some of the ways in which analyticity has been used in the past and might be used in the future to aid in performing calculations of atomic scattering amplitudes are summarized. Included are extrapolation methods, contour distortion techniques and the determination of resonance positions. '~Invited
On the basis of an approximate but nonperturbative expression for the energy shift 6E in the ground state of the hydrogen atom in the presence of an electric field of strength B, we deduce that 6E has a branch point at 8 = 0, and an asymptotic behavior SE--f -3 B In I as B-co. These properties lead
The use of the concepts of favourable and unfavourable size factor in predicting solid solubilities in metallic systems is discussed. The original concept of Hume-Rothery, Mabbott, and Channel-Evans involved the use of atomic diameters which were defined as the closest distances of approach of atom
This paper is concerned with the solution of Maxwell equations in the modelling of the scattering of a time-harmonic electromagnetic wave by an obstacle located in a two-layered medium. The use of the Silver-Mu¨ller radiation condition in each layer is shown to provide a well-posed scattering proble