Uncertainties and applications of the nuclear level density with inclusion of collective rotations

The collective rotations are included for small excitation energies in the level density of deformed nuclei by addition of a rotational band on top of each of the intrinsic levels. Estimates of the effect are given. Uncertainties of the calculations are studied in a realistic model. The calculations using different models are compared with level density observations. Examples of applications to fission probability calculations are discussed in connection with the comparison to available experimental data. The capability for predicting unknown data is thus indicated. Finally it is outlined how more flexible and thereby more useful level density expressions might be obtained. (author)