1 - IAEA Nuclear Data Services

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performed in the past [2], [3J, taking into account the
coupling between the 2 + -0 + (ground state) levels [4] (model I).
The agreement between theory and experiment was found quite
good for the angular distributions; however, in the energy-
range of a few MeV it was not possible to obtain a very good
agreement for the total cross-section. This may be due to
238
the fact that U is a rather deformed nucleus, so that an
expansion of the potential truncated at the first power of B
may not be sufficient to describe the deformation. In addition,
levels with 12-4 may give some contribution to cT. Both these
effects can be estimated using the method of the adiabatic
coupled-channel calculations [5], £6] (in this way the coupling
of all the levels of the rotational band is automatically
taken into account) and expanding the deformed potential in
terms of Legendre polinomials rather than in powers of J3
(model II).
Some calculations with the two models have been performed
using the same potential parameters as in [2], but VSQ =6.5 MeV.
The theoretical total cross-section obtained with model II is
in better agreement with the experimental one (fig. 1).
At some MeV, no significant differences were found in the
angular elastic + direct inelastic distributions given by the
two methods. This is shown in fig. 2 in which curve a) was
obtained by means of model II, whereas curve b) was obtained
using model I. Even at few MeV the differences were small.
2.3. Elastic and inelastic scattering based on microscopic description
oX the nucleus
The elastic and inelastic scattering processes of neutron from
deformed nuclei described by microscopic models have been studied.
In particular odd mass number nuclei with AS 40 have been consi­
dered.
The wave functions for different nuclear states are obtained in