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Manuscript Title: A program for calculating the angular distribution of nonrelativistic bremsstrahlung intensity.
Authors: A. Banuelos, F. Rodriguez-Trelles
Program title: BREMSSTRAHLUNG INTENSITY (NR)
Catalogue identifier: ACYJ_v1_0
Distribution format: gz
Journal reference: Comput. Phys. Commun. 15(1978)125
Programming language: Fortran.
Computer: IBM 360/50.
Operating system: DOS.
RAM: 11K words
Word size: 32
Keywords: Atomic physics, Radiation, Electron-ion, Spectroscopy, Free-free transition, X-rays, Nonrelativistic, Bremsstrahlung, Angular distribution, Polarization components.
Classification: 2.2, 21.1.

Revision history:
Type Tit le Reference
adaptation 0001 BREMSSTRAHLUNG INTENSITY 2 See below

Nature of problem:
The program calculates the angular distribution of intensity for the bremsstrahlung emission with a given photon energy from ions at rest which are bombarded by electrons of known energy. The calculation is based on Sommerfeld's results, which are valid when shielding and relativistic effects are neglected.

Solution method:
The total bremsstrahlung intensity It (integrated over all angles of observation phi) is calculated by means of Weinstock's series expansion. A fast convergent series is used to evaluate one polarization component, e.g. Iy, whereby the other components (Ix,Iz) and the angular distribution I(phi) are straightforwardly obtained.

Restrictions:
The program is restricted to photon/electron energy ratios R below R0 =~ 0.97, i.e. not close to the high energy limit. A rather large number of terms in the series expansions is required when the ratio R is larger than 0.95. For all other values of R the only restrictions arise from the error in the available values of physical constants, which amounts to less than 10 ppm. Electron energies out of the physical range of interest for bremsstrahlung emission (U/Z**2 < 0.0001 keV, with U = incident electron energy, Z= target ion atomic number) may result in an underflow condition.

Running time:
Running times range between ~ 1s for moderate energy values and ratios (E = U/Z**2 = 0.001 to 100 keV; R =0.01 to 0.85) and ~20s for high energy ratios (R<~0.95), with EPS = 10**-20.

ADAPTATION SUMMARY
Manuscript Title: Extension to high frequencies of a program for calculating the angular distribution of nonrelativistic bremsstrahlung.
Authors: A. Banuelos, F. Rodriguez-Trelles, L. Bilbao
Program title: 0001 BREMSSTRAHLUNG INTENSITY 2
Catalogue identifier: ACYJ_v1_0
Distribution format: gz
Journal reference: Comput. Phys. Commun. 17(1979)305
Programming language: Fortran.
Classification: 2.2, 21.1.

Nature of problem:
The applicability of the existing program is extended to the high frequency range of emission.

Solution method:
The total intensity It (integrated over all the angles of observation phi) is calculated by Weinstock's series expansions. Fast convergent series are used to evaluate one polarisation component (Iy=Iz), whereby the other one (Ix) and the angular distribution I(phi) are obtained. In order to reduce the computing time, near the critical energy ratio (R= hv/U ~~ Ro ~~ 0.97) intensities are obtained by interpolation.

Restrictions:
The only restrictions arise from the error in the values of the physical constants. Electron energies below 0.0001 Z**2 keV may result in an underflow condition.

Running time:
Running times range between ~~ 1 s for moderate electron energy values and ratios (E = U/Z**2 = 0.0001 to 100 keV; R=0.01 to 0.85) up to 40 s near the critical ratio Ro, with EPS = 10**-20.