High-spin states and level structure in Rb₈₄

High-spin states in Rb84 have been studied by using the Zn ₇₀(O₁₈,p₃n)Rb₈₄reaction at beam energy of 75MeV. The γ-γ coincidence, excitation function, and ratios for directional correlation of oriented states were determined. A new level scheme was established in which the positive- and negative-parity bands have been extended up to 17⁺ and 17^- with an excitation energy of about 7MeV. The signature splitting and signature inversion of the positive-parity yrast band were observed. To understand the microscopic origin of the signature inversion in the yrast positive-parity bands of doubly odd Rb nuclei, as an example, we performed calculations using the projected shell model to describe the energy spectra in Rb84. It can be seen that the main features are reproduced in the calculations. This analysis shows that the signature splitting, especially its inversion, can be reproduced by varying only the γ deformation with increasing spin. To research the deformation of Rb ₈₄ carefully, we calculate the total Routhian surfaces of positive-parity yrast states by the cranking shell model formalism. In addition, the results of theoretical calculations about the negative-parity yrast band in Rb84 with configuration π(p3/2,f5/2)-νg9/2 are compared with experimental data, and a band diagram calculated for this band is also shown to extract physics from the numerical results.