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Reorientation effect and multiple Coulomb excitation measurements have been performed for 198'2~176176176 By measuring particle spectra after Coulomb excitation of an enriched 198Hg target with 4He and 160 beams, a positive quadrupole moment of Q2 =0.66_+0.18 eb (for negative interference) or Q2 =0.80 + 0.18 eb (for positive interference) and B(E2, 0--+2)=0.991 +0.006 e 2 b z were obtained. All other B(E2) values and quadrupole moments were determined relative to these numbers from precise 7-ray yields obtained from Coulomb excitation of a frozen natHg target with 4He and 160 projectiles. Oblate shapes of all Hg isotopes were found. The data have been interpreted in terms of triaxial rotation and anharmonic vibrations.

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Deformation parameters of the positive parity yrast band and negative parity bands in S3Zr are deduced from lifetimes and E2/M1 mixing ratios. Lifetimes of high spin states have been determined from recoil distance Doppler shift and Doppler shift attenuation measurements using the S4Fe(32S, 2pn7) S3Zr reaction. Ten lifetimes and five lifetimes limits were determined. The positive parity band, built on the g9/2 K = 5/2 orbital has an average deformation [/~2[ =0.28(2), and shows a reduction of E2 transition strengths in the observed backbend region at I~g21/2 +. In contrast, the E2 strengths in the negative parity states show a steady increase up to U= 15/2-. These states are more strongly deformed than the positive parity states ([/~21=0.33(3)). The E2/M1 mixing ratios show that the negative parity band has K = 3/2 and is prolate, and favour oblate deformation for the positive parity yrast band. In the K= 1/2-band the E2 strength of the 7/2---*3/2-transition yields a deformation I/~zl = 0.26(5). The band structure is compared with calculations within the Hartree-Fock Bogoliubov cranking model.

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