Odd-even differences in moments of inertia of rare earth nuclei from the BCS theory

BCS theory is used to calculate the moments of inertia (MoI) of odd-A and e ven-even rare-earth nuclei. It is found that the large fluctuations of the odd-even differences in MoI can be reproduced through the BCS calculations, although the MoI values caloulated both for odd-A and even-even nuclei are systematically smaller then the experimental data. Contrary to the common assertion that the MoI value of odd-A nuclei are some 15% larger than that of the neighboring even-even nuclei in the BCS theory, our results confirm the conclusions made by Gregory Volkov over two decades ago. It seems helpf ul to understand the appearance of normally deformed identical bands in an odd-A nucleus and its even-even neighbors under the mean-field (BCS) approx imation.