Coulomb-gauge electrodynamics analysis of two-photon exchange in electron-atom scattering

Journal Article · Sat Nov 01 04:00:00 EST 1986 · Phys. Rev. A; (United States)

DOI:https://doi.org/10.1103/PhysRevA.34.3568· OSTI ID:5109276

Au, C K

We analyze all the time-ordered two-photon-exchange Feynman diagrams for electron-atom scattering in the Coulomb gauge. This includes the exchange of Coulomb as well as transverse photons. At threshold energy, we recover the two-photon exchange potential previously obtained by Feinberg and Sucher using covariant field-dispersion-theory technique. The present calculation is an analog of the classical work of Casimir and Polder on the two-photon exchange between a pair of neutral atoms and bridges a gap between the covariant field-dispersion-theory calculation and other nonrelativistic calculations. The Casimir effect is manifested in the first nonadiabatic potential which changes from a R/sup -6/ dependence to a R/sup -7/ dependence at asymptotic distances (R>a/..cap alpha..). We calculate terms up to the order of (hlambda/sub e//R)/sup 2/ or, equivalently, of order (a/R)/sup 4/ compared to the classical electric dipole polarization potential, and include the lowest-order energy dependence beyond the threshold. The neglected terms are of order ..cap alpha../sup 2/ or smaller at asymptotic distances. The present results are valid also for positron-atom scattering.

• Research Organization: Department of Physics, University of South Carolina, Columbia, South Carolina 29208
• OSTI ID: 5109276
• Journal Information: Phys. Rev. A; (United States), Journal Name: Phys. Rev. A; (United States) Vol. 34:5; ISSN PLRAA
• Country of Publication: United States
• Language: English

Related Subjects

640304* -- Atomic
Molecular & Chemical Physics-- Collision Phenomena
74 ATOMIC AND MOLECULAR PHYSICS
ATOM COLLISIONS
COLLISIONS
COULOMB FIELD
DIAGRAMS
DISTANCE
ELECTRIC FIELDS
ELECTRODYNAMICS
ELECTRON COLLISIONS
ELECTRON-ATOM COLLISIONS
FEYNMAN DIAGRAM
INTERACTION RANGE