PROGRAM SUMMARY
Title of program:
CCFULL
Catalogue identifier:
ADKM
Ref. in CPC:
123(1999)143
Operating system: UNIX
Number of lines in distributed program, including test data, etc:
3073
Programming language used: Fortran
Computer: DEC
Nature of physical problem:
It has by now been well established that fusion reactions at energies
near and below the Coulomb barrier are strongly influenced by couplings
of the relative motion of the colliding nuclei to several nuclear
intrinsic motions. Recently, precisely measured fusion cross sections
have become available for several systems, and a distribution of the
Coulomb barrier, which is originated from the channel couplings, have
been extracted. It has been pointed out that the linear coupling
approximation, which has often been used in coupled-channels
calculations, is inadequate in order to analyze such high precision
experimental data. The program CCFULL solves the coupled-channels
equations to compute fusion cross sections and mean angular momenta of
compound nucleus, taking into account the couplings to all orders.
Method of solution
CCFULL directly integrates coupled second order differential equations
using the modified Numerov method. The incoming wave boundary
condition is employed and a barrier penetrability is calculated for each
partial wave. Nuclear coupling matrix elements are evaluated by using
the matrix diagonalisation method once the physical space has been
defined.
Restrictions on the complexity of the program
The program is best suited for systems where the number of channels
which strongly couple to the ground state is relatively small and where
multi-nucleon transfer reactions play less important role compared with
inelastic channels. It also relies on an assumption that the fusion
process is predominantly governed by quantum tunnelling over the Coulomb
barrier. This assumption restricts a system which the program can
handle to that where the sum of the charge of the projectile and the
target nuclei Zp + ZT is larger than around 12 and the charge product
ZpZT less than around 1800. For most of experimental data which were
measured to aim to extract fusion barrier distributions, this condition
is well satisfied. The program also treats a vibrational coupling in
the harmonic limit and a rotational coupling with a pure rotor. The
program can be modified for general couplings by directly providing
coupling strengths and excitation energies.
Typical running time
A few seconds for input provided. The computer time depends strongly
upon the number of channels to be included. It will considerably
increase if one wishes to include a large number of channels, as for
instance 20.