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[Licence| Download | New Version Template] adkf_v1_0.tar.gz(72 Kbytes)
Manuscript Title: BARRIER code: calculation of fission barriers.
Authors: F. Garcia, O. Rodriguez, J. Mesa, J.D.T. Arruda-Neto, V.P. Likhachev, E. Garrote, R. Capote, F. Guzman
Program title: BARRIER
Catalogue identifier: ADKF_v1_0
Distribution format: tar.gz
Journal reference: Comput. Phys. Commun. 120(1999)57
Programming language: Fortran.
Computer: Intel 80386+80387.
Operating system: MS-DOS 6.00, Windows 95 and NT 4.0.
RAM: 108M words
Word size: 16
Keywords: Nuclear physics, Collective model, Fission barrier, Nuclear deformation, Liquid-drop model, Independent-particle, Model, Nuclear energy levels, Woods-saxon potential, Cassini ovaloids.
Classification: 17.20.

Nature of problem:
Average values of various nuclear properties are only explained on the average by liquid drop model (where the average might be taken over particle number or, alternatively, over deformation). To reproduce other aspects of nuclear structure, such as ground state spins and energy spectra, it was found elsewhere that a different description was necessary. In this regard, we calculated single particle energies as functions of the deformation parameters of an axially deformed Woods Saxon potential, as input to the shell correction calculations. To get the total nuclear energy, it is also necessary to add a pairing energy in order to take into consideration the short range nuclear interactions, which are not taken into account in the mean field approximation. Many works found in literature deal with potential energy surface and calculated mass by using the Strutinsky Method. Bjornholm and Lynn pointed out the impact caused by an adequate description of parametrization in each calculation. In particular, many details in the description of fission processes, like fission issomers and angular distribution, are sensitive to the choice of parametrization. Some previous works pointed out the advantages of Cassini ovaloids parametrization for very deformed shape calculations. The numerical code BARRIER, proposed and used in this work, calculates the potential energy surface in the Strutinsky semi-microscopical approach using the Cassini ovaloids shape parametrization for the nuclear potential.

Solution method:
The Cassini ovaloids shape parametrization is used for nuclear average field description. The Woods Saxon level scheme is obtained at any point of the deformation space. The single-particle level scheme is used to calculate the shell model and pairing corrections to the liquid drop energy in the Strutinsky approach. The BCS method is used in pairing correction calculations, using the 42 levels near the Fermi level. The standard Liquid Drop Model expressions are adopted to calculate the smooth part of the total potential energy.

The use of the standard Liquid Drop Model expressions does not allow the the use of the code in calculations with nuclei far from the beta-stability line. The implemented parametrization does not contain the gamma-non axial degrees of freedom. The n-p residual interaction and the exact conservation of partial number of particles is not considered in the usual BCS method implemented in the code.

Running time:
Depends on the choice for calculations. For a particular set of deformations the running time is approximately 10 seconds.