High-spin g factors and proton alignment in ^180,182,184Pt

The average g factors of high-spin states in ^180,182,184Pt were measured by the transient-field technique. In all three isotopes the quasicontinuum g factor at an angular momentum of ∼ 20ℏ is (g) ∼ 0.37. This contrasts with similar measurements on other nuclei that have 70 ≤ Z ≤ 80, where typical values of 〈g〉 ∼ 0.22 have been attributed to the influence of quasineutron alignments. Evidently proton and neutron configurations are about equally important at high spin in the Pt isotopes near midshell. This inference is consistent with the discrete spectroscopy, including the contention, supported by g_K - g_R values, that h_9/2 proton pairs align along with the i _13/2 neutrons at rotational frequencies of ℏω ≈ 0.3 MeV in ¹⁸⁴Pt. Links between the quasicontinuum g factors and features in the discrete spectroscopy are explored by comparing and contrasting the behavior of ¹⁸⁴Pt and ¹⁶⁶Hf.