skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Band properties of the transitional nucleus {sup 187}Pt

Abstract

High-spin states in {sup 187}Pt have been studied experimentally using the {sup 173}Yb({sup 18}O, 4n) reaction at beam energies of 78 and 85 MeV. The previously known bands based on the {nu}i{sub 13/2},{nu}7/2{sup -}[503], and {nu}i{sub 13/2}{sup 2}{nu}j configurations have been extended to high-spin states, and new rotational bands associated with the {nu}3/2{sup -}[512] and {nu}1/2{sup -}[521] Nilsson orbits have been identified. The total Routhian surface calculations indicate that the transitional nucleus {sup 187}Pt is very soft with respect to {beta} and {gamma} deformations. The band properties, such as level spacings, band crossing frequencies, alignment gains, and signature splittings, have been compared with the systematics observed in neighboring nuclei and have been interpreted within the framework of the cranked shell model. The rotational bands show different band crossing frequencies, which can be explained by the alignment either of i{sub 13/2} neutrons or of h{sub 9/2} protons. Importantly, evidence is presented for a {pi}h{sub 9/2} alignment at very low frequency in the {nu}7/2{sup -}[503] band. The proton nature of the band crossing is strongly suggested by comparing the measured B(M1;I{yields}I-1)/B(E2;I{yields}I-2) ratios with the theoretical values from the semiclassical Doenau and Frauendof approach.

Authors:
;  [1];  [2]; ; ; ; ; ;  [1]; ; ; ; ; ; ;  [3];  [2];  [4]
  1. Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China)
  2. (China)
  3. Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195 (Japan)
  4. (Japan)
Publication Date:
OSTI Identifier:
20995127
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. C, Nuclear Physics; Journal Volume: 75; Journal Issue: 3; Other Information: DOI: 10.1103/PhysRevC.75.034314; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; HIGH SPIN STATES; MEV RANGE 10-100; NEUTRONS; OXYGEN 18; PLATINUM 187; PROTONS; ROTATIONAL STATES; SEMICLASSICAL APPROXIMATION; SHELL MODELS; YTTERBIUM 173

Citation Formats

Zhou, X. H., Xing, Y. B., Graduate School of the Chinese Academy of Sciences, Beijing 100049, Liu, M. L., Zhang, Y. H., Guo, Y. X., Ma, L., Lei, X. G., Guo, W. T., Oshima, M., Toh, Y., Koizumi, M., Osa, A., Hatsukawa, Y., Xu, F. R., Sugawara, M., Department of Technical Physics and MOE Key Laboratory, Peking University, Beijing 100871, and Chiba Institute of Technology, Narashino, Chiba 275-0023. Band properties of the transitional nucleus {sup 187}Pt. United States: N. p., 2007. Web. doi:10.1103/PHYSREVC.75.034314.
Zhou, X. H., Xing, Y. B., Graduate School of the Chinese Academy of Sciences, Beijing 100049, Liu, M. L., Zhang, Y. H., Guo, Y. X., Ma, L., Lei, X. G., Guo, W. T., Oshima, M., Toh, Y., Koizumi, M., Osa, A., Hatsukawa, Y., Xu, F. R., Sugawara, M., Department of Technical Physics and MOE Key Laboratory, Peking University, Beijing 100871, & Chiba Institute of Technology, Narashino, Chiba 275-0023. Band properties of the transitional nucleus {sup 187}Pt. United States. doi:10.1103/PHYSREVC.75.034314.
Zhou, X. H., Xing, Y. B., Graduate School of the Chinese Academy of Sciences, Beijing 100049, Liu, M. L., Zhang, Y. H., Guo, Y. X., Ma, L., Lei, X. G., Guo, W. T., Oshima, M., Toh, Y., Koizumi, M., Osa, A., Hatsukawa, Y., Xu, F. R., Sugawara, M., Department of Technical Physics and MOE Key Laboratory, Peking University, Beijing 100871, and Chiba Institute of Technology, Narashino, Chiba 275-0023. Thu . "Band properties of the transitional nucleus {sup 187}Pt". United States. doi:10.1103/PHYSREVC.75.034314.
@article{osti_20995127,
title = {Band properties of the transitional nucleus {sup 187}Pt},
author = {Zhou, X. H. and Xing, Y. B. and Graduate School of the Chinese Academy of Sciences, Beijing 100049 and Liu, M. L. and Zhang, Y. H. and Guo, Y. X. and Ma, L. and Lei, X. G. and Guo, W. T. and Oshima, M. and Toh, Y. and Koizumi, M. and Osa, A. and Hatsukawa, Y. and Xu, F. R. and Sugawara, M. and Department of Technical Physics and MOE Key Laboratory, Peking University, Beijing 100871 and Chiba Institute of Technology, Narashino, Chiba 275-0023},
abstractNote = {High-spin states in {sup 187}Pt have been studied experimentally using the {sup 173}Yb({sup 18}O, 4n) reaction at beam energies of 78 and 85 MeV. The previously known bands based on the {nu}i{sub 13/2},{nu}7/2{sup -}[503], and {nu}i{sub 13/2}{sup 2}{nu}j configurations have been extended to high-spin states, and new rotational bands associated with the {nu}3/2{sup -}[512] and {nu}1/2{sup -}[521] Nilsson orbits have been identified. The total Routhian surface calculations indicate that the transitional nucleus {sup 187}Pt is very soft with respect to {beta} and {gamma} deformations. The band properties, such as level spacings, band crossing frequencies, alignment gains, and signature splittings, have been compared with the systematics observed in neighboring nuclei and have been interpreted within the framework of the cranked shell model. The rotational bands show different band crossing frequencies, which can be explained by the alignment either of i{sub 13/2} neutrons or of h{sub 9/2} protons. Importantly, evidence is presented for a {pi}h{sub 9/2} alignment at very low frequency in the {nu}7/2{sup -}[503] band. The proton nature of the band crossing is strongly suggested by comparing the measured B(M1;I{yields}I-1)/B(E2;I{yields}I-2) ratios with the theoretical values from the semiclassical Doenau and Frauendof approach.},
doi = {10.1103/PHYSREVC.75.034314},
journal = {Physical Review. C, Nuclear Physics},
number = 3,
volume = 75,
place = {United States},
year = {Thu Mar 15 00:00:00 EDT 2007},
month = {Thu Mar 15 00:00:00 EDT 2007}
}
  • High-spin states in {sup 189}Pt have been studied with the in-beam gamma-spectroscopy method via the {sup 176}Yb({sup 18}O,5n) reaction at beam energies of 88 MeV and 95 MeV. A new level scheme of {sup 189}Pt has been established. Rotational bands based on the upsiloni{sub 13/2}{sup -1}, upsilonf{sub 5/2}(p{sub 3/2}) and upsiloni{sub 13/2}{sup -2}upsilonf{sub 5esol2}(p{sub 3/2}) configurations, as well as several structures with irregular level spacings, have been observed. Properties of rotational bands have been analyzed in the framework of triaxial particle-rotor model. A gammaapprox-30 deg. triaxial shape and a near prolate shape have been proposed to the upsiloni{sub 13/2}{sup -1}more » and upsilonf{sub 5/2}(p{sub 3/2}) bands, respectively. Two DELTAI = 2 transition sequences with similar energies have been observed, and they have been proposed to be associated with the upsiloni{sub 13/2}{sup -2}upsilonf{sub 5/2}(p{sub 3/2}) configuration. According to the relevant Nilsson orbitals, the bands built on the upsiloni{sub 13/2}{sup -2}upsilonf{sub 5/2}(p{sub 3/2}) configuration could be interpreted as a pair of pseudo-spin partner.« less
  • High-spin states in {sup 189}Pt have been studied experimentally using the {sup 176}Yb({sup 18}O,5n) reaction at beam energies of 88 and 95 MeV. The level scheme of {sup 189}Pt has been revised significantly and extended to high-spin states. Rotational bands have been analyzed in the framework of triaxial particle-rotor model, and a {gamma}{approx_equal}-30 deg. triaxial shape and a near-prolate shape have been proposed to the {nu}i{sub 13/2}{sup -1} and {nu}f{sub 5/2}(p{sub 3/2}) bands, respectively. Two {delta}I=2 transition sequences with similar energies have been observed, and they have been proposed to be associated with the {nu}i{sub 13/2}{sup -2}{nu}f{sub 5/2}(p{sub 3/2}) configuration.more » The structure built on the {nu}i{sub 13/2}{sup -2}{nu}f{sub 5/2}(p{sub 3/2}) configuration could be interpreted as a pair of pseudospin partners. The level energies in the pseudospin partner bands are well reproduced by the theoretical calculations of the triaxial particle-rotor model if a near-oblate shape is assumed.« less
  • The decay scheme of 2.35-h / sup 187/Pt was investigated using isotopically separated samples produced by the IS0LDE facility at CERN. A total of 20 excited levels in /sup 187/Ir was established. For many of these levels, spin, parity and absolute probabilities of depopulating transitions were determined. The results indicate that the /sup 187/Ir nucleus can be described in terms of a single-particlc Nilsson model including Coriolis coupling between bands (3/2 + STA402!, 1/2 + STA400!). (13 figures, 7 tables) (auth)
  • The appearance of a decoupled band in $sup 187$Pt and a normal band in $sup 185$Pt from the $sup 174$Yb, $sup 176$Yb ($sup 16$O,5n) reaction allows a shape transition from oblate to prolate to be predicted between these two nuclei. (FR)