The nuclear magnetic moment of "Ir and the directional distribution of gamma rays in "Os
Angular distributions of gamma transitions between levels in I9OOs fed in the decay of I9'Ir aligned in a rhenium single crystal have been measured at temperatures down to 2 mK. Multipole mixing ratios in both gamma and electron-capture transitions are deduced and compared with various nuclear models. The angular distribution coefficients are applied to interpret very small anisotropies observed when I9'Ir is polarised in an iron host matrix, cooled to 2.5 mK. The deduced magnetic dipole moment of the 4 + ground state of I9'Ir is Ip(I9'Ir; GS)~ = 0.04( l)pN. Possible single-particle descriptions compatible with this result are suggested. NUCLEAR MOMENTS: I9'Ir (from Re(a, n)): measured I,(@ from oriented nuclei in single crystal Re and polycrystalline Fe: deduced I9OOs S(E2/M1), Jp in electron capture, lpl(1901r ground state).
Nuclear Data Sheets for A=190
Abstract Nuclear spectroscopic information for known nuclides of mass number 190 (W,Re,Os,Ir,Pt,Au,Hg,Tl,Pb,Bi,Po) has been evaluated and presented together with adopted energies, Jπ, and decay modes of levels in these nuclei. This evaluation supersedes earlier (1990Si09,1982Le22,1973Sc42) Nuclear Data Sheets for A=190.
Negative parity states in odd-mass Ir and au nuclei
Abstract The decays of 193 Os → 193 Ir , 191 Pt → 191 Ir , 189 Pt → 189 Ir and 193 Hg → 193 Au have been studied in γ-γ coincidences, internal conversion and electron-electron delayed coincidences. New levels with the following spin-parity assignments and half-lives are proposed: 193Ir: 299.45±0.09keV, I π = 7 2 − , T 1 2 = 0.19±0.03 ns ; 598.26±0.l5keV, I π = 3 2 − ; 740.46±0.15keV, I π = 5 2 − . 191Ir: 391.14±0.05 keV, I π = 7 2 − , T 1 2 = 0.24±0.02 ns ; 659.06±0.08 keV, I π = 3 2 − , T 1 2 ns . 189Ir: 615.70±0.08 keV, I π = 7 2 − , T 1 2 = 0.18±0.02 ns ; 1184.54±0.11 keV, I π = 5 2 − , T 1 2 ns . The 508 keV 7 2 − level in 193Au was found to have T 1 2 = 0.29±0.02 ns . In each nucleus these negative parity states and the 11 2 − isomeric state are strongly connected with E2 and Ml transitions and only weakly connected to the low-lying positive parity states. The B(E2) values are close to the values of B(E2; 2+ → 0+) in the neighbouring even nuclei. We propose these negative parity level systems to be associated with an essentially spherical shape of the nuclei in contrast to the low-lying positive parity states (including the ground state) of these nuclei, which in Ir are likely to be deformed states.