Microscopic description of octupole-phonon alignment in the actinides

A microscopic model, based on an approach that combines the ideas of the cranking model and the random-phase approximation, is formulated for the description of the vibrational octupole states. The mean field is approximated by a rotating Nilsson potential with allowance for monopole pairing. The residual interaction is made up of separable octupole--octupole interactions of the isoscalar and isovector types with negative signature. An empirical formula establishing a relation between the vibrational excitation energy and the aligned vibrational angular momentum as a function of the angular velocity is proposed. The alignment of the vibrational octupole angular momentum for the states of the K/sup π/ = 0- band of the /sup 230,232/Th and /sup 238/U nuclei is analyzed. A qualitative correspondence of the nature of the branching of the electric dipole transitions from the octupole states into the yrast-line states in these nuclei is obtained