Abstract
The () reaction at MeV has been used to study five isotopes of Os () which lie in a transition region between the deformed rare earths and spherical nuclei. Cross sections and angular distributions have been measured to states up to about 2 MeV of excitation in all cases except and in which states were seen up to 4 MeV. The energies of the states which we see and their summed cross sections in percent of the ground state (in parenthesis) are: 913 (4.7), 1551 (1.8), and 1734 keV (6.3) in , 1087 (5.7), 1480 (3.7), 1705 (1.2), and 1765 keV (<1) in , and 1042 (8.4) and tentatively 1982 (1.2) and 2268 keV (1.3) in . The transitions seen in the odd isotopes are at 9.8, 77, 730, and 1657 keV in and 1070 and 1213 keV in . The results show no positive evidence for the existence of strongly populated shape isomeric states similar to those seen in the transition region around . In and possibly the lowest exicted and bands have the properties expected for two phonon vibrations. In addition to the rotational excitations in the odd isotopes, two strong transitions have been seen to states at 599 and 802 keV in which we have postulated to be the vibrations based on the [510] state with admixed one quasiparticle components. Similar states have been seen in . The lowest transfers to states in were found to have significantly lower intensity than the ground states in the adjacent even- nuclei. In the case of the low lying strength is split between two states. Calculations have been made to understand these phenomena in terms of blocking effects and Coriolis mixing.
NUCLEAR REACTIONS , MeV; measured ; deduced levels, ; pairing plus DWBA calculations, comparison with expt. for lowest states.
- Received 22 December 1975
DOI:https://doi.org/10.1103/PhysRevC.13.2288
©1976 American Physical Society