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Manuscript Title: Hauser-Feshbach nuclear scattering subroutine LIANA.
Authors: W.R. Smith
Program title: LIANA
Catalogue identifier: ABKA_v1_0
Distribution format: gz
Journal reference: Comput. Phys. Commun. 1(1970)181
Programming language: Fortran.
Computer: CDC 6400.
Operating system: SCOPE 3.1.6A.
RAM: 23K words
Word size: 60
Keywords: Nuclear physics, Reaction, Compound nucleus, Hauser Feshbach, Differential Cross section, Integrated cross section, Optical Model, Woods-saxon, Spin-orbit, Penetrabilities, Width-fluctuation Correction, Compound-elastic.
Classification: 17.10.

Subprograms used:
Cat Id Title Reference
ACQF_v1_0 SCAT CPC 1(1969)106
ACQF_v1_0 0002 ADAPT SCAT TO LIANA CPC 1(1969)181

Nature of problem:
Subroutine LIANA computes the scattering angular distribution and integrated cross section for any two-particle nuclear reaction which proceeds through a statistical distribution of compound nucleus states. The subroutine may be incorporated into other programs or else run with the driver program provided. The latter calls subroutine SCAT to obtain the necessary optical model nuclear penetrabilities. The input required consists of the energies, charges, masses, spins, parities, and optical model parameters for all two-particle channels through which the compound nucleus can decay.

Solution method:
The Hauser-Feshbach theory generalized to include spin-orbit coupling is employed. Either the plain Hauser-Feshbach method implying independence of compound nucleus formation and decay or the modified Hauser-Feshbach procedure including a correction for an assumed Porter- Thomas distribution of compound nucleus resonance widths may be utilized.

Restrictions:
Only particle channels can be treated; gamma-ray channels are excluded. Nor can channels containing three or more separate particles be handled. In any channel the spin-orbit particle can have spin up to 5 and the other particle may have any spin. The maximum number of partial waves necessary in any one channel can be no greater than 31. A total of ten types of two particle partitions, and a total of 600 channels, may be simultaneously treated. The restrictions on maximum spin, number of partial waves, number of particle types, and number of channels are due solely to storage allotments and may be easily relaxed.

Running time:
The running time is roughly proportional to the number of penetrabilities calculated, since the rest of the calculation is short by comparsion. The calculational time spent by LIANA alone increases as the values of the spin, number of channels, and number of partial waves increase. The test case requires 13 seconds to compile and 3 seconds to run on a CDC 6400 computer.