PROGRAM SUMMARY
Title of program:
BARRIER
Catalogue identifier:
ADKF
Ref. in CPC:
120(1999)57
Distribution format: uuencoded compressed tar file
Operating system: MS-DOS 6.00, Windows 95 and NT 4.0
High speed store required:
108MK words
Number of bits in a word:
16
Number of lines in distributed program, including test data, etc:
8721
Programming language used: Fortran
Computer: Intel 80386+80387
Nature of physical 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.
Method of solution
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.
Restrictions on the complexity of the problem
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.
Typical running time
Depends on the choice for calculations. For a particular set of
deformations the running time is approximately 10 seconds.