Restrictions on shape-coexistence descriptions of A ~ 150 nuclei from the 156Dy(p, t) 154Dy reaction

1992 ◽  
Vol 70 (12) ◽  
pp. 1236-1240 ◽  
Author(s):  
Tao Qu ◽  
D. G. Burke
Keyword(s):  
Rotational Energy ◽  
Spherical Nucleus ◽  
Shape Coexistence ◽  
Reaction Products ◽  
Ground State Band ◽  
The Third ◽  
Population Pattern ◽  
State Band ◽  
Spherical Nuclei ◽  
Mev Protons

The 156Dy(p, t),154Dy reaction was studied, using 20 MeV protons and a magnetic spectrograph to analyze the reaction products. This reaction on the "deformed" target 156Dy has three strong L = 0 transitions populating levels in the "spherical" nucleus 154Dy at 0, 661, and 1058 keV with relative strengths of 100:74:16, respectively. This population pattern is similar to those observed in the isotones 152Gd and,150Sm, in which the third 0+ bands have been interpreted as deformed bands coexisting in spherical nuclei. However, the third 0+ band in 154Dy has a rotational energy spacing as large as that for the ground-state band, which suggests that it does not have a large deformation, and its (p, t) strength is significantly less than those for the corresponding states in the samarium and gadolinium isotones. This restricts the shape-coexistence interpretation of excited 0+ states in 154Dy. The systematics suggest that,152Gd is probably also not as good an example of shape coexistence as 150Sm.

Levels in 153Gd and 155Gd Studied with the (p,t) Reaction

1973 ◽  
Vol 51 (12) ◽  
pp. 1369-1376 ◽  
Author(s):  
G. Løvhøiden ◽  
D. G. Burke ◽  
J. C. Waddington
Keyword(s):  
Mixed State ◽  
Ground State ◽  
Present Experiment ◽  
Vibrational State ◽  
Vibrational Band ◽  
Ground State Band ◽  
State Band ◽  
Mev Protons

States in 153Gd and 155Gd have been populated with (p,t) reactions induced by 18 MeV protons. In 155Gd, strong l = 0 transitions were found to the 3/2−[521] ground state and the 3/2− β-vibrational state. Excited rotational members of the ground state band and the β-vibrational band were also identified. Strong l = 0 transitions were observed to the ground state, the 129, 509, and 531 keV levels in 153Gd. The population of members of the previously suggested ground state band in 153Gd confirms the earlier 3/2−[521] assignment. It is proposed that the 129 keV level is a mixed state of which the major component may be the 3/2 1/2−[530] Nilsson state. The 509 keV (3/2−) and 549 keV (5/2−) levels populated in the present experiment are probably members of a β-vibrational band in 153Gd. No explanation is offered for the strongly populated 3/2− level at 531 keV.

A Study of Levels in 153Gd Using the (d,t) and (3He,α) Reactions

1973 ◽  
Vol 51 (22) ◽  
pp. 2354-2368 ◽  
Author(s):  
G. Løvhøiden ◽  
D. G. Burke
Keyword(s):  
Cross Sections ◽  
Negative Parity ◽  
Positive Parity ◽  
Angular Distributions ◽  
Reaction Products ◽  
Ground State Band ◽  
Intensity Pattern ◽  
Nilsson Model ◽  
State Band ◽  
Photographic Emulsions

Triton spectra from the 154Gd(d,t)153Gd reaction have been measured at 15 angles using a beam of 15 MeV deuterons. The 154Gd(3He,α)153Gd reaction was studied at 4 angles with a 24 MeV 3He beam. The reaction products were analyzed with an Enge-type magnetic spectrograph and detected with photographic emulsions. The (d,t) angular distributions and ratios of the (3He,α) and (d,t) cross sections were used to determine l values for a number of transitions. Members of the strongly perturbed band consisting of a mixture of Nilsson states from the i13/2 shell have been populated. An attempt has been made to describe some of the positive parity states in terms of the Nilsson model with Coriolis and ΔN = 2 mixings included. As spin assignments are now available for a large number of positive parity levels, it is possible to see a better developed pattern for this mixing than was presented previously. Although the observed intensity pattern for the 3/2−[521] ground-state band agrees with expectations, the remaining negative parity states cannot be easily explained in terms of the basic Nilsson model.

The ground state band of25Mg studied by electron scattering

1975 ◽  
Vol 1 (2) ◽  
pp. L13-L17 ◽  
Author(s):  
E W Lees ◽  
C S Curran ◽  
S W Brian ◽  
W A Gillespie ◽  
A Johnston ◽  
...  
Keyword(s):  
Electron Scattering ◽  
Ground State ◽  
Ground State Band ◽  
State Band

scholarly journals NEW STRUCTURES IN 178HF AND COULOMB EXCITATION OF ISOMERS

2011 ◽  
Vol 20 (02) ◽  
pp. 474-481 ◽  
Author(s):  
A.B. HAYES ◽  
D. CLINE ◽  
C. Y. WU ◽  
A.M. HURST ◽  
M.P. CARPENTER ◽  
...  
Keyword(s):  
Angular Momentum ◽  
Ground State ◽  
Coulomb Excitation ◽  
National Laboratory ◽  
Argonne National Laboratory ◽  
Particle Detector ◽  
Ground State Band ◽  
Rotational Bands ◽  
Coincidence Data ◽  
State Band

A 985 MeV 178 Hf beam was Coulomb excited by a 208 Pb target at the ATLAS accelerator of Argonne National Laboratory. Gammasphere and the CHICO particle detector recorded particle-γ coincidence data. The aim was to populate and determine the mechanism of previously observed Coulomb excitation of the Kπ = 6+ (t1/2 = 77 ns ), 8- (4 s ) and 16+ (31 y ) isomer bands. New rotational bands were identified including an aligned band which appears to mix with the ground-state band (GSB) and the γ-vibrational band above ~ 12 ħ of angular momentum. Newly observed γ-decay transitions into the three isomer bands may elucidate the K-mixing which allows Coulomb excitation of these isomer bands, but direct decays from the GSB into the 16+ isomer band have not yet been confirmed.

Spin Alignment of the Ground-State Band Levels in Nd and Sm Isotopes Excited in (α, 2nγ) Reactions

1972 ◽  
Vol 33 (6) ◽  
pp. 1515-1521 ◽  
Author(s):  
Hiroyasu Ejiri ◽  
Tokushi Shibata ◽  
Akira Shimizu ◽  
Kohsuke Yagi
Keyword(s):  
Ground State ◽  
Ground State Band ◽  
Spin Alignment ◽  
State Band

scholarly journals Variational procedure leading from Davidson potentials to the E(5)and X(5) critical point symmetries

2020 ◽  
Vol 13 ◽  
pp. 10
Author(s):  
Dennis Bonatsos ◽  
D. Lenis ◽  
N. Minkov ◽  
D. Petrellis ◽  
P. P. Raychev ◽  
...  
Keyword(s):  
Phase Transition ◽  
Critical Point ◽  
Ground State ◽  
Nuclear Energy ◽  
Energy Spectra ◽  
Variational Procedure ◽  
Ground State Band ◽  
Sharp Maximum ◽  
State Band ◽  
Shape Phase Transition

Davidson potentials of the form β^2 + β0^4/β^2, when used in the original Bohr Hamiltonian for γ-independent potentials bridge the U(5) and 0(6) symmetries. Using a variational procedure, we determine for each value of angular momentum L the value of β0 at which the derivative of the energy ratio RL = E(L)/E(2) with respect to β0 has a sharp maximum, the collection of RL values at these points forming a band which practically coincides with the ground state band of the E(5) model, corresponding to the critical point in the shape phase transition from U(5) to Ο(6). The same potentials, when used in the Bohr Hamiltonian after separating variables as in the X(5) model, bridge the U(5) and SU(3) symmetries, the same variational procedure leading to a band which practically coincides with the ground state band of the X(5) model, corresponding to the critical point of the U(5) to SU(3) shape phase transition. A new derivation of the Holmberg-Lipas formula for nuclear energy spectra is obtained as a by-product.

GAS–LIQUID CHROMATOGRAPHY OF TERPENES: PART II. THE DEHYDRATION PRODUCTS OF α-TERPINEOL

1961 ◽  
Vol 39 (1) ◽  
pp. 1-12 ◽  
Author(s):  
E. Von Rudloff
Keyword(s):  
Liquid Chromatography ◽  
Oxalic Acid ◽  
Complex Mixture ◽  
Reaction Times ◽  
Gas Liquid Chromatography ◽  
Minor Components ◽  
Reaction Products ◽  
The Third ◽  
Major Reaction ◽  
Trace Constituents

The complex mixture of terpenes obtained on dehydrating α-terpineol with aqueous oxalic acid was almost completely separated by gas–liquid chromatography (GLC), using rapeseed oil as a new liquid phase. Terpinolene, dipentene, α- and γ-terpinene, Δ2,4(8)-p-menthadiene, and 1,8-cineole were identified as the major reaction products; three minor and seven trace constituents were also detected. One of the minor components was p-cymene, one an oxide, and the third an unidentified hydrocarbon. The yield of these components after different reaction times was determined by GLC. The initial dehydration gives terpinolene and dipentene in the ratio of approximately 2:1. Terpinolene is isomerized to α- and γ-terpinene, Δ2,4,(8)-p-menthadiene, and the unidentified hydrocarbon, but not to dipentene. 1,8-Cineole and the other oxide are formed in a reversible reaction. Dehydration of α-terpineol with several other acidic reagents yielded mixtures of products similar to that obtained with aqueous oxalic acid. With acetic acid or acetic anhydride, however, dipentene was formed preferentially and this reaction appears to proceed via the derived acetate.

Ground-state band inSe72

1977 ◽  
Vol 15 (3) ◽  
pp. 939-949 ◽  
Author(s):  
K. P. Lieb ◽  
J. J. Kolata
Keyword(s):  
Ground State ◽  
Ground State Band ◽  
State Band

scholarly journals Konversionselektronen von 156Gd nach Neutroneneinfang / The Conversion Electron Spectrum of the Reaction 155Gd(n,e)156Gd

1974 ◽  
Vol 29 (1) ◽  
pp. 17-30
Author(s):  
K. Schreckenbach
Keyword(s):  
Ground State ◽  
Conversion Electron ◽  
Electron Spectrum ◽  
Vibrational Band ◽  
Ground State Band ◽  
Conversion Electron Spectrum ◽  
State Band

The conversion electron spectrum of the reaction 155Gd (n, e) 156Gd has been measured up to 8.5 MeV. The results below 4.5 MeV are presented and multipolarities are determined with these results. E0 admixtures of the Δ I = 0 transitions from the 0 + β-vibrational band to the ground state band were determined with 15% accuracy. 156Gd level schemes are discussed and extended by new spin and parity assignments.

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