Changes in rotational characters of one- and two-phonon gamma-vibrational bands in 105Mo

Abstract

The γ vibration is the most typical low-lying collective motion prevailing the nuclear chart. But only few one-phonon rotational bands in odd-A nuclei have been known. Furthermore, two-phonon states, even the band head, have been observed in a very limited number of nuclides not only of odd-A but even-even. Among them, that in 105 Mo is unique in that Coriolis effects are expected to be stronger than in 103 Nb and 105 Nb on which theoretical studies were reported. Then the purpose of the present work is to study 105 Mo paying attention to rotational character change of the one-phonon and two-phonon bands. The particle-vibration coupling model based on the cranking model and the random-phase approximation is used to calculate the vibrational states in rotating odd-A nuclei. The present model reproduces the observed yrast zero-phonon and onephonon bands well. Emerging general features of the rotational character change from low spin to high spin are elucidated. In particular, the reason why the one-phonon band does not exhibit signature splitting is clarified. The calculated collectivity of the two-phonon states, however, is located higher than observed.