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Three superdeformed bands have been observed in ${}^{191}$Au using the EUROGAM II multidetector array. The previously known yrast superdeformed band has been extended up to very high rotational frequencies and two new excited bands have been assigned to this nucleus. These bands behave as signature partners and display characteristics which suggest they could be based either on the $\ensuremath{\pi}$ [532]3/2 orbital alone or on that orbital plus the $\ensuremath{\pi}$ [530]1/2 orbital, which become the $[\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{431}]$3/2,1/2 doublet in the pseudospin formalism.

High resolution spectra from fast proton radiative capture in {sup 208}Pb are presented for three energies of the incident protons: 14.8, 15.7, and 16.9 MeV. The collected spectra were analyzed with emphasis on the region of capture to unbound states in order to search for possible structure and to study the competition between two basically different phenomena: the statistical process versus the fluctuation effects in radiative capture to unbound final states. In the energy region of incoming protons considered in our experiment, the statistical processes modeled with a Hauser-Feshbach calculation dominate. The spectra of primary {gamma} rays, coincident with the low energy one from the decay of the f{sub 7/2} single-particle state, show a prominent structure which is predominantly of g{sub 9/2} character. The calculations of continuum spectra based on the extended direct-semidirect model and the Hauser-Feshbach statistical approach successfully reproduce the experimental data.

The high-spin normally deformed and superdeformed states of ${}^{194}\mathrm{Hg}$ have been populated in an exit channel of the ${}^{16}{\mathrm{O}+}^{186}\mathrm{W}$ reaction at 110 MeV bombarding energy. The Doppler shift analysis of the energies of the \ensuremath{\gamma} transitions de-exciting both normally deformed and superdeformed states in ${}^{194}\mathrm{Hg}$ indicates a lower recoil velocity of the ${}^{194}\mathrm{Hg}$ nucleus compared to that of the ${}^{196}\mathrm{Pb}$ nucleus obtained from the $6n$ exit channel of the complete-fusion compound nucleus. This suggests that incomplete fusion plays the main role in the population of normally deformed and superdeformed states of ${}^{194}\mathrm{Hg}$ in this reaction.

The level scheme of Au-190 was extended up to high spin using gamma spectroscopy with the Eurogam-II array and internal conversion measurements with the electron- gamma spectrometer of Orsay. Sever ...

The level scheme of Au-191 was considerably extended to high spin using gamma spectroscopy with the Eurogam-II array and internal conversion measurements with the Orsay electron spectrometer. Several bands that appear as strongly coupled were associated with low- Omega configurations in Au-191 . Using total routhian surface and cranked shell model calculations it was shown that these bands have a rotation-aligned nature and are most likely generated by the nonaxiallity of the nucleus induced by the odd proton. The predictions for the presence of such bands in Au-191 and in the oblate nuclei in the Pt-Au-Hg region found excellent agreement with the experimental data, as well as the predictions for their alignments and band-crossing frequencies in Au-191 .

Excited states in Ta-164 were populated in the Nd-142(Al-27,5n)Ta-164 reaction and investigated using the AFRODITE spectrometer Arran. The yrast rotational decay sequence Lip to spin 21(-) is identified for the first time and assigned to the pi[514]9/2(-) x nu[660]1/2(+) configuration. A less intense. excited hand is also identified. Low-spin signature inversion is observed in the yrast band, and is compared with the extended total Routhian surface calculations. It is likely that quadrupole pairing plays a role in generating the anomalous signature splitting, but an additional mechanism apart front the assumed mean field and quadrupole pairing interaction may be required to account for the experimental data.

Excited isomeric states ${I}^{\ensuremath{\pi}}{=20}^{+}$ have been identified for the first time in odd-odd ${}^{190,192}\mathrm{Au}$ nuclei. Two independent measurements of their half-lives were performed, using the recoil shadow anisotropy method with the Eurogam-II data, and using the time distribution of K-electron lines from the Orsay electron-spectrometer data. Half-lives of $7.0\ifmmode\pm\else\textpm\fi{}0.3$ and $5.4\ifmmode\pm\else\textpm\fi{}0.3$ ns were obtained for these isomers in ${}^{190}\mathrm{Au}$ and ${}^{192}\mathrm{Au},$ respectively, by the latter measurements. The $\ensuremath{\pi}{h}_{11/2}^{\ensuremath{-}1}\ensuremath{\bigotimes}\ensuremath{\nu}{i}_{13/2}^{\ensuremath{-}2}{h}_{9/2}^{\ensuremath{-}1}$ configuration was assigned to these isomeric states. A shape transition towards highly triaxial deformation with $\ensuremath{\gamma}\ensuremath{\sim}\ensuremath{-}90\ifmmode^\circ\else\textdegree\fi{}$ is suggested by total Routhian surface calculations, which could be the cause for their relatively hindered decay.

Excited states in ${}^{165}\mathrm{Ta}$ were populated in the ${}^{142}\mathrm{Nd}{(}^{27}\mathrm{Al}{,4n)}^{165}\mathrm{Ta}$ and ${}^{141}\mathrm{Pr}{(}^{28}\mathrm{Si}{,4n)}^{165}\mathrm{Ta}$ reactions and investigated using the AFRODITE array. The yrast rotational decay sequence up to spin ${53/2}^{\ensuremath{-}}$ is identified and assigned to the $[514]{9/2}^{\ensuremath{-}}$ configuration. The nuclear shape is investigated using total Routhian surface calculations. The experimental results are discussed in relation to existing data in the neighboring Ta isotopes and results from cranked shell model calculations. Unexpectedly large signature splitting, for a high-$\ensuremath{\Omega}$ configuration, is observed in the yrast band. Further discrepancies are observed between theoretical and experimental values for the band crossing frequency and signature splitting of the $B(M1)/B(E2)$ ratios. The possibility that these discrepancies are a consequence of a large deviation from an axially symmetric nuclear shape is investigated.