Transition strengths in 79Rb.

Abstract

High angular momentum states in $^{79}\mathrm{Rb}$ were populated via the $^{63}\mathrm{Cu}$${(}^{19}$F,2pn${)}^{79}$Rb and $^{65}\mathrm{Cu}$${(}^{18}$O,4n${)}^{79}$Rb reactions. The 65 MeV $^{19}\mathrm{F}$ and 65 MeV $^{18}\mathrm{O}$ beams were provided by the Florida State University FN Tandem accelerator. Prompt \ensuremath{\gamma}-\ensuremath{\gamma} coincidences were measured for both reactions. Two additional \ensuremath{\gamma} cascades have been assigned to $^{79}\mathrm{Rb}$, including a new high-excitation structure dominated by dipole transitions. Firm spin assignments were made for the first time for a number of states by means of directional correlation ratios and an angular distribution measurement using the $^{63}\mathrm{Cu}$${(}^{19}$F,2pn) reaction. The Doppler-shift attenuation method was used to determine lifetimes for states and their respective side-feeding times in both the yrast positive-parity and yrast negative-parity states. Transition quadrupole moments were deduced from the transition strengths and compared with those predicted by Woods-Saxon cranking calculations. The energy spacings and mixing ratios were compared with particle-rotor calculations.