scholarly journals Study of the Q.Q interaction

2018 ◽  
Vol 27 (07) ◽  
pp. 1850056
Author(s):  
Arun Kingan ◽  
Xiaofei Yu ◽  
Larry Zamick
Keyword(s):  
Shell Model ◽  
Quadrupole Interaction ◽  
Single Particle ◽  
Ground State ◽  
Ground State Band ◽  
Rotational Model ◽  
Model Calculations ◽  
State Band

We perform shell model calculations using a quadrupole–quadrupole interaction (Q.Q). We show results in single j shell spaces and the full S-D shell. We show that one gets useful results with Q.Q in both spaces. We emphasize the importance of the choice of single particle energies in order to obtain the results of Elliott using a Q.Q interaction without the momentum terms. We show a [Formula: see text] spectrum for a ground state band but with [Formula: see text]’s different from the rotational model. We also show results such as [Formula: see text] and [Formula: see text] excited “spin bands”. (The latter can also be expressed as a [Formula: see text] band). We find spectra starting with [Formula: see text] which have both even [Formula: see text] and odd [Formula: see text] members.

scholarly journals Single particle energies and nuclear g factors

2017 ◽  
Vol 26 (09) ◽  
pp. 1750053 ◽  
Author(s):  
Shadow Robinson ◽  
Larry Zamick
Keyword(s):  
Shell Model ◽  
Single Particle ◽  
Ground State ◽  
Particle State ◽  
Complex Interplay ◽  
Model Calculations ◽  
Effective Interactions ◽  
State Splitting ◽  
State Affect ◽  
Nuclear Shell

Adding one neutron to doubly magic [Formula: see text]Sn, we can associate the low lying states in[Formula: see text]Sn with single particle states. Thus, the [Formula: see text] and [Formula: see text] states are identified as the [Formula: see text] and [Formula: see text] single particle states, respectively. In [Formula: see text]Sn, these two low lying states are separated by an energy of 0.172[Formula: see text]MeV. Currently, there is a dispute as to the ordering of these states. We examine how the two scenarios, selecting [Formula: see text] as the ground state or [Formula: see text] as the ground state, affect spectra and nuclear [Formula: see text] factors of higher mass Sn isotopes in a variety of shell model situations. Significantly, this includes examining the complex interplay of the choice of single particle state splitting, effective interactions, and effective [Formula: see text]-factors in nuclear shell model calculations. Of particular importance is how the trends in the calculated results for [Formula: see text] factors diverge from recent experimental measurements for the higher mass isotopes of Sn.

scholarly journals g-factors of some excited states in 49,50Cr

2019 ◽  
Vol 3 ◽  
pp. 205
Author(s):  
A. A. Pakou ◽  
J. Billowes ◽  
A. W. Mountford ◽  
C. Tenreiro ◽  
D. D. Warner
Keyword(s):  
Magnetic Field ◽  
Excited States ◽  
Ground State ◽  
Experimental Error ◽  
Magnetic Moments ◽  
Transient Field ◽  
Ground State Band ◽  
Model Calculations ◽  
State Band ◽  
G Factors

Magnetic moments of the first excited states in 50Cr and of the 7/2" and 19/2' states in 49Cr, have been measured by the transient field technique. The states were excited by the inverse reaction 40Ca + 12C and the recoil nuclei traversed a thick gadolinium foil. The observed rotations, of the 2+, 4+, 6+, 8+ states of the ground-state band in 50Cr, were found into the experimental error to be the same, suggesting similar g-factors for these states and thus supporting a high collectivity for the ground-state band, g-factors of the 7/2' and 19/2 states in 49Cr, were deduced by adopting both an overall parametrization of the transient magnetic field in Gd and by comparing the 49Cr rotations with rotations of states with known magnetic moments, as the 2+ ones of 50Cr and of 46Ti which was also populated in the same reaction. Both methods gave similar results and the g-factors adopted for the 19/2" and 7/2" states were + 0.78(17) and +0.35(7) respectively. These results are discussed in terms of cranked shell model calculations and are found to support a proton alignment in the f7/2 shell.

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.

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.

scholarly journals Excitation of the Ground-State Rotational Band in 28Si by Inelastic Scattering of 25.25 MeV Polarized Protons

1973 ◽  
Vol 51 (12) ◽  
pp. 1293-1299 ◽  
Author(s):  
R. de Swiniarski ◽  
H. E. Conzett ◽  
C. R. Lamontagne ◽  
B. Frois ◽  
R. J. Slobodrian
Keyword(s):  
Inelastic Scattering ◽  
Cross Sections ◽  
Ground State ◽  
Optical Potential ◽  
Great Sensitivity ◽  
Angular Distributions ◽  
Rotational Model ◽  
Coupled Channels ◽  
Polarized Protons ◽  
State Band

Angular distributions of the analyzing power and cross sections have been measured for the elastic and inelastic scattering of 25.25 MeV protons exciting the K = 0+ ground-state band in 28Si. Good agreement with experiment is obtained in the coupled-channels formalism on the basis of the rotational model with a quadrupole deformation β2 = −0.40 (oblate) and a hexadecapole deformation β4 = +0.15. The calculations show the great sensitivity of the experimental results to both the magnitude and sign of the quadrupole and hexadecapole deformations. Equivalent fits of the data were obtained either by keeping the deformation length of the various deformed terms of the optical potential constant (δ0 = β0R0 = βIRI = βLSRLS) or by increasing the deformation of the spin–orbit optical potential relative to the central potential by a factor of 1.5 (βLS = 1.5βcent).

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