Large scale shell model calculations for odd-odd 58−62^{58-62}Mn isotopes

Large scale shell model calculations have been carried out for odd-odd $^{58-62}$Mn isotopes in two different model spaces. First set of calculations have been carried out in full $\it{fp}$ shell valence space with two recently derived $\it{fp}$ shell interactions namely GXPF1A and KB3G treating $^{40}$Ca as core. The second set of calculations have been performed in ${fpg_{9/2}}$ valence space with the $fpg$ interaction treating $^{48}$Ca as core and imposing a truncation by allowing up to a total of six particle excitations from the 0f$_{7/2}$ orbital to the upper $\it{fp}$ orbitals for protons and from the upper $\it{fp}$ orbitals to the 0g$_{9/2}$ orbital for neutron. For low-lying states in $^{58}$Mn, the KB3G and GXPF1A both predicts good results and for $^{60}$Mn, KB3G is much better than GXPF1A. For negative parity and high-spin positive parity states in both isotopes $fpg$ interaction is required. Experimental data on $^{62}$Mn is sparse and therefore it is not possible to make any definite conclusions. More experimental data on negative parity states is needed to ascertain the importance of 0g$_{9/2}$ and higher orbitals in neutron rich Mn isotopes.Comment: 5 pages, 4 figures, Submitted to Eur. Phys. J.

Extended investigation of superdeformed bands in 151,152^{151,152}Tb nuclei

A detailed study of known and new SD bands in Tb isotopes has been performed with the use of the EUROBALL IV -ray array. The high-statistics data set has allowed for the extension of known SD bands at low and high spins by new -ray transitions. These transitions, as it turns out, correspond to the rotational frequencies where the principal superdeformed gaps (Z=66,N=86) close giving rise to up- or down-bending mechanisms. This enables to attribute the underlying theoretical configurations with much higher confidence as compared to the previous identifications. Five new SD bands have been discovered, three of them assigned to the 152Tb and the two others to the 151Tb nuclei. Nuclear mean-field calculations have been used to interpret the structure of known SD bands as well as of the new ones in terms of nucleonic configurations

High-spin study of rotational structures in 72Br

High-spin states in 3572Br37 were studied using the 40Ca(36Ar, 3pn) reaction. The existing level scheme has been significantly modified and extended. Evidence has been found for a spin reassignment of -1ℏh to the previously observed negative-parity band, which carries implications for the interpretation of a signature inversion in this structure. One signature of the previously assigned positive-parity band is interpreted as negative parity and has been extended to I π=(22-) and its signature partner has been observed up to Iπ = (19-) for the first time. The remaining positive-parity band has been extended to Iπ=(29+). A sequence of states observed to Iπ=(22+) may be the signature partner of this structure. Configurations have been assigned to each of these three structures through comparisons to cranked Nilsson-Strutinsky calculations

An investigation into high-spin properties of the N = 86 isotones "1"5"2Dy and "1"5"3Ho

SIGLEAvailable from British Library Document Supply Centre-DSC:DXN014514 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Neutron-proton pairing, Coulomb effects and shape coexistence in odd-odd N= Z 46V

High-spin states up to the f7/2-shell band termination at J? = 15+ have been observed in the odd-odd N = Z = 23 nucleus V. A revised and significantly extended level scheme contains two distinct structures corresponding to spherical and prolate shapes. A band exhibiting rotational-like behaviour in the latter structure has excellent correspondence with the yrast sequence in Ti and is therefore assumed to be a T = 1 configuration. The difference between excited analogue states in the two nuclei is interpreted as a Coulomb effect and its variation with spin associated with np-pair alignment effects in V. Shell-model calculations have been performed and are in good quantitative agreement with experimental level energies. The competition between T = 1 and T = 0 structures is also reproduced. © 1999 Elsevier Science B.V. All rights reserved.Scientific Committee on Antarctic Research Engineering and Physical Sciences Research Council Komitet Badan Naukowych Natural Sciences and Engineering Research Council of Canada Engineering and Physical Sciences Research CouncilThe authors thank both Alfredo Poves and Alex Brown for permission to use results from their shell model codes and for helpful discussions. We also thank those responsible for all aspects of the PEX collaboration. This work was supported by the United Kingdom Engineering and Physical Sciences Research Council (EPSRC) from whom D. E. Appelbe was in receipt of an EPSRC studentship. A. Maj is grateful to the Polish State Committee for Scientific Research for partial financial support (KBN Grant No. 2 P03B 001 16). This work was also supported by the Danish Natural Science Research Council

Deformed rotational cascades in 152Dy: Further evidence for shape coexistence at high spin

Two new rotational bands have been observed in the 152Dy nucleus following experiments performed using the EUROGAM ?-ray spectrometer. Several transitions have been observed that link these new bands into the known single-particle states. Using the Doppler shift attenuation method, the quadrupole moment of the previously-known rotational sequence has been measured. The value of Qband=3.85±0.06 e b confirms the deformed nature of this cascade. The structures of the three bands are discussed in terms of the occupation of both paired and unpaired orbitals, and are found to be in good agreement with theoretical calculations. The observation of two new bands further extends the concept of shape coexistence in the 152Dy nucleus

Nonyrast high-spin states in N=Z 44Ti

High-spin states have been investigated in the N-Z=22 nucleus 44Ti. A newly observed set of states with J?=6+ , 8 + , 10+ , and 12+ are assigned to be members of a band built upon an excited 0+ state. This band displays rotational-like level spacings, with a near-linear J(J+1) dependence. A third set of J?=8+ , 10+ , and 12+ states have also been tentatively assigned and a negative-parity intruder band has been extended to J? =13-. Comparisons with df-shell model calculations show a good agreement for both energy levels and branching ratios. These calculations indicate that the excited 0+ band is dominated by a mixture of 8p-4h and 6p-2h configurations relative to 40Ca

Gamma-ray spectroscopy of high spin states near N = Z in the f7/2 shell

EG and G ORTEC;Polish State Committee for Scientific ResearchProceedings of the 1998 33rd Zakapone School of Physics, International Conference on Nuclear Physics -- 1 September 1998 through 9 September 1998 -- Zakopane -- 55236Two pairs of mirror-nuclei, 2549Mn/2449Cr and 2447Cr/2347V, and the odd-odd N = Z nucleus 2346V have been studied up to the f7/2-shell band termination states. Differences in energy between isobaric analogue states in these nuclei have been measured and interpreted in terms of Coulomb effects. Through this work, we have shown that Coulomb energies are extremely sensitive to nuclear effects such as particle alignments, band terminations and shape changes. This has allowed us to investigate the extent to which the Coulomb energy can be used as a probe of the nuclear structure

High-spin states following multi-nucleon transfer

High-spin states in neutron-rich nuclei, populated following deep-inelastic multi-nucleon transfer, have been studied using the GAMMASPHERE array at the LBNL, USA. A $^{64}$Ni beam at an energy $\sim 15\%$ above the Coulomb barrier was incident upon a thick $^{208}$Pb target, leading to the population of more than 130 different nuclei. The strongest channels correspond to nuclei close to the projectile and target, although transfer of up to 50 nucleons has been observed. New high-spin states in neutron-rich $^{60,62}$Fe and $^{68,70,72}$Zn nuclei have been observed. Some limitations of this method of high-spin spectroscopy are discussed, including the apparent difficulty of populating odd-odd and odd-even isotopes via this type of reaction. The data have been searched for superdeformed (SD) states in the $A=$ 190–200 region, but no evidence for their presence has been found