In-beam study of 80Kr; Quasiparticle excitations in nuclei around mass 80

Recoil distance lifetime measurements in82Kr

“…4, the energy E'(co) in the rotating frame, E'(co)=(E(I + 1)+E(I-1))/2-hcolx(co ), is plotted versus the rotational frequency co. The crossings of the ground band with the S-band in 82Kr and 84Sr occur at 450-500keV, in good agreement with the figures derived for 8~ and other A~80 Kr and Rb isotopes [2,21]. Dewald et al [20] attributed the second 8 + state in 848r to a second band crossing involving an aligned (g9/2) 2 proton configuration.…”

“…In a recent study, Funke et al [2] used two-quasiparticle excitation to explain the up-and backbending and reduced E2 transition probabilities of the yrast states at about U=8 + in 7s'S~ It was suggested that this is due to a crossing of the gsb with the S-band arising from the alignment of two g9/2 protons. Further evidence for the g9/2 proton character of the S-band in 7SKr comes from the spectrum of the g9/2 decoupled proton band in 79Rb for which no backbending has been observed [19], because the S-band is blocked.…”

“…Recent extensive studies of the level structures of the krypton, rubidium and strontium isotopes have revealed rapid changes of the quadrupole deformation as a function of neutron holes in the N=50 shell closure at the isotopes *6Kr, 87Rb and 88Sr [1][2][3]. In the even krypton isotopes 74-80, level energies and v-transition strengths of the ground state, gamma and octupole bands have been established up to rather high spin values (I~14+).…”

“…19). In addition to the collective picture of 78, SOKr ' two-quasiparticle excitations have very recently been introduced as the expla-* Work supported by Deutsches Btmdesministerium far Forschung und Technologie i Permanent address: University of Helsinki, Finland nation of the backbending and reduced E2 transition probabilities of the yrast band at U~8 § [2]. The spectrum of 82Kr has been investigated by means of the reaction 8~ S2Kr [71], by Coulomb excitation [8,9], inelastic proton scattering [10] and the /Ldecay of 82Rb and S2Br [11].…”

High-spin structure of104Pd

“…Compared to the yrast band, band 10 shows an alignment gain of ∼4h, so it is assumed to be configured by two quasiparticles. As more two-quasineutron structures are not expected below bands 3,4,5 [41][42][43][44][45], and assigned to noncollective νg 9/2 ,(p 1/2 ,f 5/2 ) configurations [45]. In Pd isotopes with proton number Z = 46, analogous two-quasiproton excitations can be expected.…”