Nuclear Moments of Inertia

The problem of nuclear moments of inertia is considered taking into account the effect of the internal motion phenomenologically. The kinetic energy of the internal motion is assumed to take the form of that of a symmetrical top. When the interactions between the irrotational and the internal motions are strong, the total system has a rotational energy spectrum whose moment of in ertia is given by the sum of those of two motions. By means of the empirical data for the electric quadrupole excitations. their magnitudes are estimated. In consequence the internal motion is shown to be very important. Comparison with other methods is carefully examined, especially with the work by Hayakawa and Marumori. (auth)