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Excited states in 208Fr have been identified using the 197Au(16O, 5n)208Fr reaction and a variety of time-correlated $ \gamma$ -ray and conversion electron spectroscopic techniques. Transitions above and below a $ \tau$ = 623(16) ns 10- isomer are placed in the level scheme. This isomer is analogous to that observed in the odd-odd isotone 206At for which additional spectroscopic information is also obtained, including a precise lifetime of $ \tau$ = 1173(30) ns. The $ \gamma$ -rays assigned to 208Fr are the same as the main transitions erroneously assigned to 209Fr in previous work. [ABSTRACT FROM AUTHOR]

A very reliable and complete set of data on the one proton one neutron hole levels in 208Bi is available. Spectroscopic factors for proton transfer to 207Pb and neutron pick up from 209Bi have been measured. Recently and conversion electron spectroscopy with the 208Pb(p,n)208Bi reaction has clarified some questionable points of the level scheme and provided -branching ratios. The matrix elements of the shell model residual interaction are calculated by a least square fit from these data. The nondiagonal elements are very sensitive to the -branching; therefore for the first time an extensive set could be determined. A comparison of this "measured" interaction with a realistic interaction calculated from the interaction between free nucleons shows remarkably good agreement. [ABSTRACT FROM AUTHOR]

Abstract: Adopted spectroscopic information on pure E0 transitions has been deduced by critical evaluation of the available experimental data for all even–even nuclei ranging from to . Values of , the ratio of the K-conversion electron intensity of the , E0 transition to that of the , E2 transition, have been determined. This procedure, together with the most recent theoretical coefficients for internal conversion and electron–positron pair creation, as well as electronic factors, produced a large number of new X(E0/E2) values, defined as the dimensionless ratio of the absolute B(E0) and B(E2) transition rates. The squared value of the monopole transition strength, ρ 2(E0), has been deduced using the best available 0+-level half-lives and branching ratios. [Copyright &y& Elsevier]

A seven-quasiparticle isomer withandT1/2 = 53 ( + 3-7) ns has been identified in179Ta. By comparing its excitation energy with results from multi-quasiparticle calculations that include the effects of blocking and residual nucleon-nucleon interactions, the isomer is assigned the(5/2 +[402], 7/2 +[404],(5/2-[512], 7/2-[514], 7/2-[503], 9/2 +[624]) configuration. The decay of this isomer is found to be unusually fast, a feature that is attributed to a mixing with a specific collective level. The interaction strength is found to be orders of magnitude lower than that observed between interacting collective levels. [ABSTRACT FROM AUTHOR]

A previous compilation of excitation energies Ex (31−) and reduced electric-octupole transition probabilities B(E3;01+→31−) for first 3− states of even-even nuclides, which covered the literature to March 1988, has been updated to cover the literature to the end of 2000. Data obtained from various experimental procedures are tabulated. The final table presents adopted values of B(E3;01+→31−), together with the E3 transition strengths &z.sfnc;M(E3)&z.sfnc;2 in Weisskopf units. Plots of &z.sfnc;M(E3)&z.sfnc;2 versus mass number A, atomic number Z, and neutron number N confirm the existence of structure suggested in the earlier work. [Copyright &y& Elsevier]

Lifetime measurements of states in nuclei with A=187 and 188 have been performed, using reactions between 155Gd and 36Ar and following the transport of evaporation residues to the focal plane of a gas-filled recoil separator. In a separate experiment using the 159Tb(32S, 4n) reaction the γ-decay of isomeric levels in 187Tl has been studied using delayed γ-γ coincidence measurements. From observation of their subsequent γ decay, the mean lifetimes were measured to be 1000 ± 55 ns and 1600 ± 100 ns. Although it was not possible to characterize the isomers completely, they are proposed as candidates for one-proton, two-neutron excitations. In the course of this study, the decay of an isomer in 188Pb was also observed and its lifetime was measured as 1150 ± 30 ns, and limits of 20–600 ns were placed on the meanlife of an isomer conjectured in 187Pb. [ABSTRACT FROM AUTHOR]

Excited states in the range of even tungsten isotopes, from170W to178W, populated in the β-decay of170–178Re parents have been identified using γ-ray singles and coincidence techniques, utilising the high efficiency of a Compton-suppressed array, and conversion electron systems. Many new states at low excitation energies have been identified, complementing the level schemes previously established from in-beam studies. The new states include excited O+ states in170W,172W,174W,176W and178W. A large body of data on decay properties, spins and parities, and relative E2 and E0 matrix elements has been obtained. The properties of the K π=0+ (quasi-β) bands are compared with similar bands observed in light osmium, platinum and mercury isotopes, which have been attributed to shape coexistence. [ABSTRACT FROM AUTHOR]

γ-spectra and excitation functions of theMo( p, nγ)Tc reaction were measured in the 1.2-3.6 MeV proton energy range by using thick, enriched targets, Ge(Li) and low energy photon (hyperpure Ge) spectrometers. These detectors were used in γγ-coincidence experiments, too. Conversion electron spectrum measurements were performed by means of a superconducting magnet transporter Si(Li) spectrometer (SMS) at E =4 MeV and multipolarities of some transitions have been determined. Based on the experimental results a level scheme ofTc has been constructed. Level energies ofTc were calculated on the basis of the parabolic rule, derived from the cluster-vibration model. [ABSTRACT FROM AUTHOR]

Transient-field precessions were measured simultaneously for the 2 states ofOs as ions of these nuclei traversed a thin polarized iron foil. In contrast with most earlier measurements, the relative gyromagnetic ratios deduced here are independent of the level lifetimes. Emphasis is placed upon determination of the g-factor of the first excited state inOs, as disparities in measurements of the lifetimes of this level have led to uncertainties in its g-factor. [ABSTRACT FROM AUTHOR]

The conversion electron and γ-ray spectra of theZr( p, n γ)Nb reaction were measured with Ge(Li) and superconducting magnet transporter Si(Li) spectrometers respectively, at 4MeV bombarding proton energy. The multipolarities of some transitions were determined and conclusions were drawn on the spins and parities of the excited states ofNb. [ABSTRACT FROM AUTHOR]