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Manuscript Title: The radiation tail accompanying elastic electron scattering from the atomic nucleus.
Authors: I. Talwar, L.E. Wright
Program title: RADTAIL
Catalogue identifier: ABJV_v1_0
Distribution format: gz
Journal reference: Comput. Phys. Commun. 55(1989)367
Programming language: Fortran.
Computer: CRAY X-MP.
Operating system: COS.
RAM: 42K words
Word size: 64
Keywords: Nuclear physics, Coulomb excitation, Tail radiation, Dirac-coulomb, Electron scattering.
Classification: 17.13.

Nature of problem:
The radiation tail accompanying elastic electron scattering from an extended nucleus with atomic number A and charge Z is calculated by distorted-wave methods.

Solution method:
The radial integral over a spherical Bessel function and incoming and outgoing electron wave functions which are solution to the Dirac equation with the static Coulomb field present is divided into two parts: the internal and external integrals. The internal integral is done numerically since the Dirac-Coulomb solutions are generated numerically. The external integral is evaluated in terms of a matrix series of incomplete gamma functions. Non-penetrating integrals (point Dirac-Coulomb integrals) are evaluated by means of a matrix series. The summation over photon multipoles is aided by forming ratios of large angular momentum contributions to the corresponding plane wave contributions which can be summed analytically.

The present code has been checked and the dimensions have been made large enough for photon multipoles up to 30 which is adequate for incident electron energies up to 150 MeV and photon energies up to 80% of the incident electron energy. In principle, the code will work at higher energies, but the dimensions would have to be increased and the computation time will increase dramatically.