High-spin states in ${}_{}{}^{192}{}_{}{}^{}\mathrm{Tl}$, excited through the ${}_{}{}^{181}{}_{}{}^{}\mathrm{Ta}$(${}_{}{}^{18}{}_{}{}^{}\mathrm{O}$,$7n$) and ${}_{}{}^{181}{}_{}{}^{}\mathrm{Ta}$(${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$,$5n$) reactions, were studied using in-beam $\gamma$-ray spectroscopic techniques. Excitation functions, activity spectra, $\gamma$-ray angular distributions, and multidimensional coincidences were measured. The strongly Coríolis-distorted $\tilde{\pi }{h}_{\frac{9}{2}}\times \tilde{\nu }{i}_{\frac{13}{2}}$ two-quasiparticle band already known in the heavier ${}_{}{}^{194,196,198}{}_{}{}^{}\mathrm{Tl}$ isotopes has also been found in this case based on an $I^{\pi }=8^{-}$ isomeric state at 250.6 keV above the known long-lived $7^{+}$ level. Trends already noted in the other Tl isotopes and also predicted by two-quasiparticle plus-rotor model calculations are confirmed thus reinforcing such a theoretical description.

NUCLEAR REACTIONS ${}_{}{}^{181}{}_{}{}^{}\mathrm{Ta}$(${}_{}{}^{18}{}_{}{}^{}\mathrm{O}$,$\mathrm{xn}\gamma$), $E=105-125\mathrm{}$ MeV; ${}_{}{}^{181}{}_{}{}^{}\mathrm{Ta}$(${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$,$\mathrm{xn}\gamma$), $E=95-105\mathrm{}$ MeV; measured $E_{\gamma }$, $I_{\gamma }$, $\sigma (E, E_{\gamma }, {\theta }_{\gamma })$, $\gamma -\gamma$ coin.; ${}_{}{}^{192}{}_{}{}^{}\mathrm{Tl}$ levels deduced, $J$, $\pi$, $T_{\frac{1}{2}}$. Natural target. Ge(Li) detectors.

• Received 18 July 1979

DOI:https://doi.org/10.1103/PhysRevC.21.933