The Search for πf_7/2 Intruder States in ⁷³As

Proton occupation of the f_7/2 orbital (the πf_7/2 configuration) in the mass A ∼ 70 region is rare since it would require large prolate shape deformation (β₂ ≥ 0.4). So far, there are only two known cases of such an occupation in this region (⁷¹As and ⁶⁷Cu). The aim of this study was to search for evidence of πf_7/2 states in ⁷³As. High-spin states in ⁷³As were populated using the ¹⁴C(⁶²Ni, p2n) reaction at 50 MeV performed at Florida State University. A Compton-suppressed Ge detector array made up of three Clover detectors and seven single-crystal detectors was used to record γ−γ coincidences. Directional correlation of oriented nuclei ratios (R_DCO) were used to assign spins. Coincidence data showed no evidence of an f_7/2 band structure. Furthermore, a state at 577 keV that was previously thought to have a spin of 7/2 (and which could be the head of a πf_7/2 band) was instead determined to have a spin of 5/2 based on R_DCO measurements. These results suggest that there is no πf_7/2 orbital occupation in ⁷³As.