  In this work, the reliability of the Landau expression for the nuclear level
density calculations is tested, for the first-time, to describe nuclear level
densities of some light, intermediate mass and heavy nuclei at excitations
corresponding to discrete and s-wave neutron resonance energies. The chi-2
minimizing method is used in treatment of the experimental data for the two
suggested energy range of discrete energies given by Nuclear Data Sheet [1] and
by the systematic for nuclear level density parametrization in [2]. Our
comparison with the related data in the discrete energy range has shown that
the results obtained by the Landau expression are better than those of
back-shifted Fermi-gas model and constant temperature approximation. This
result is also valid for some nuclei of interest when the s-wave neutron
resonance level density is included to check theoretical prescriptions in the
energy range from initial bound states to unbound states near the neutron
binding energy.
