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The calculation of absorption and elastic cross sections using the optical potential
(2-13' COMPUTER PItYSICS COMMUNICATIONS 3 11972) 173-179. NORTH-HOLLAND PUBLISHING COMPANY
THE CALCULATION OF ABSORPTION AND ELASTIC CROSS SECTIONS USING THE OPTICAL POTENTIAL Arthur C. ALLISON Smithonian Astrophysical Observatory, Cambridge, Massachusetts 02138, USA Received 3 January 1972
PROGRAM SUMMARY Title o f program: SCATTERING BY COMPLEX POTENTIAL Catalog~te number: AACF Computer: CDC 6400. Installation: Smithsonian Astrophysical Observatory, Cambridge. Massachusetts 02138, USA Operating system: SCOPE 3/35 Programming laogztages used: FORTRAN High speed store reqzdred: 12500 words. No. o f bits ht a word: 60 Is the program overlaid? No No. o f magnetic tapes required: None What other peripherals are used? Card Reader; Line Printer No. o]cards in combined program and test deck: 625
Ko,words: Atomic, Potential, Complex Potential, Optical Model, Optical Potential, Schrfdinger Equation, Numerov, Scattering, Absorption, Cross Section, Phase Shift. Nature o f physical problem "Iqle absorption of particles by a centre of force may be represented by introducing a complex potential I 11. The absorption and elastic cross sections are given in terms of the real and imaginary parts of the phase shift obtained from the solution of the Schr6dinger equation with a complex potential. Method o f solution This program is similar to one published earlier by Smith [2] that also allows scattering by a complex potential to be studied. The present program permits greater flexibility in the form of the potential and also uses an improved Numerov scheme [31 for integrating the differential equations. Restrictions on the complexity o f the problem The program can be easily modified to accept non-Coulomb potential energy functions of any form rather than the complex spherical well that is used in this version.
Typical runnhzg time The time depends critically on the number of points in the integration mesh. For the test case, which required two hundred points, three complex phases were generated each second. Umlsual features o]program The computation time of the numerical integration is halved because of the symmetry of the problem and the use of the iterative Numerov method [31. References [ll N.F. Mott and H.S.W. Massey, The theory of atomic collisigns, 3rd. Ed. (Clarendon Press, Oxford, 1965) p. 184.
12] W.R. Smith, Computer Phys. Commun. 1 (I 969) 106. [31 A.C. Allison, J. Comp. Phys. 6 (1970) 378.
THE CALCULATION OF ABSORPTION AND ELASTIC CROSS SECTIONS USING THE OPTICAL POTENTIAL Arthur C. ALLISON Smithonian Astrophysical Observatory, Cambridge, Massachusetts 02138, USA Received 3 January 1972
PROGRAM SUMMARY Title o f program: SCATTERING BY COMPLEX POTENTIAL Catalog~te number: AACF Computer: CDC 6400. Installation: Smithsonian Astrophysical Observatory, Cambridge. Massachusetts 02138, USA Operating system: SCOPE 3/35 Programming laogztages used: FORTRAN High speed store reqzdred: 12500 words. No. o f bits ht a word: 60 Is the program overlaid? No No. o f magnetic tapes required: None What other peripherals are used? Card Reader; Line Printer No. o]cards in combined program and test deck: 625
Ko,words: Atomic, Potential, Complex Potential, Optical Model, Optical Potential, Schrfdinger Equation, Numerov, Scattering, Absorption, Cross Section, Phase Shift. Nature o f physical problem "Iqle absorption of particles by a centre of force may be represented by introducing a complex potential I 11. The absorption and elastic cross sections are given in terms of the real and imaginary parts of the phase shift obtained from the solution of the Schr6dinger equation with a complex potential. Method o f solution This program is similar to one published earlier by Smith [2] that also allows scattering by a complex potential to be studied. The present program permits greater flexibility in the form of the potential and also uses an improved Numerov scheme [31 for integrating the differential equations. Restrictions on the complexity o f the problem The program can be easily modified to accept non-Coulomb potential energy functions of any form rather than the complex spherical well that is used in this version.
Typical runnhzg time The time depends critically on the number of points in the integration mesh. For the test case, which required two hundred points, three complex phases were generated each second. Umlsual features o]program The computation time of the numerical integration is halved because of the symmetry of the problem and the use of the iterative Numerov method [31. References [ll N.F. Mott and H.S.W. Massey, The theory of atomic collisigns, 3rd. Ed. (Clarendon Press, Oxford, 1965) p. 184.
12] W.R. Smith, Computer Phys. Commun. 1 (I 969) 106. [31 A.C. Allison, J. Comp. Phys. 6 (1970) 378.