Reorientation measurements in 20Ne and 22Ne

doi:10.1016/0370-2693(69)90256-1

Physics Letters B

Volume 29, Issue 2, 14 April 1969, Pages 103-104

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Abstract

The static quadrupole moments of the first excited J^π=2⁺ states in ²⁰Ne and ²²Ne are deduced from measurements of the reorientation effect in Coulomb excitation with ³²S ions. The values obtained are Q(2⁺) = − 0.27 ± 0.11 b and Q(2⁺) = − 0.21 ± 0.06 b for ²⁰Ne and ²²Ne, respectively.

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Cited by (36)

Measurement of the average l ionization probability of gold in 25 MeV iodine-gold collisions
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A study of 22Ne with the 20Ne(t, p) reaction
1974, Nuclear Physics, Section A
The ²⁰Ne(t, p)²²Ne reaction has been studied at 15 and 20 MeV bombarding energies covering excitation energies up to 12 MeV. The protons were observed in a magnetic spectrograph with an energy resolution of 30–35 keV FWHM. The proton angular distributions are analyzed empirically as well as with DWBA methods and several final-state spin-parity assignments are made. The DWBA analysis shows that there are important higher-order contributions to the reaction mechanism. A comparison of the 15 MeV (t, p) data with corresponding (τ, p) data leads to the identification of 10 isobaric analog pairs in the mass-22 system. DWBA predictions based on theoretical wave functions are compared to the data and the overall trends agree reasonably well.
Antipairing and antistretching in 22Ne
1974, Nuclear Physics, Section A
The ground state rotational band of ²²Ne has been investigated with the angular momentum and particle number projected Hartree-Bogoliubov theory. Variation before projections was performed in the framework of the constrained Hartree-Bogoliubov theory with the quadrupole moment and the degree of pairing as constraints. It is shown that there is a clear decrease of the pairing correlations (antipairing) and a decrease of the quadrupole deformation (antistretching) with increasing angular momentum. The antipairing effect appears to be essential to reproduce the experimentally known deviation of the spectrum from the J(J + 1) rule. The antistretching indicated by the B(E2) values is much stronger than that indicated by the calculated static quadrupole moments. This amounts to a breakdown of the rotational picture which is possibly connected with the low band cut-off values in the sd shell. The antipairing effect decreases the antistretching only slightly. The interaction between the pairing and quadrupole degrees of freedom is found to be too weak to change the earlier conclusions concerning antipairing and antistretching in the whole sd shell. No inert core was assumed in the calculations. The effective G-matrix elements of the Hamada-Johnston potential were used as an interaction.
Quadrupole moments of nuclear excited states measured by the reorientation effect in coulomb excitation
1973, Atomic Data and Nuclear Data Tables
Quadrupole moments of nuclear excited states measured by the reorientation effect in coulomb excitation
1973, NUCL.DATA TABLES SER.A
Reorientation measurements using the doppler-shift method: static quadrupole moments of 20Ne, 22Ne, 24Mg, 26Mg and 28Si
1972, Nuclear Physics, Section A
The static quadrupole moments of the first excited I^π = 2⁺ states in ²⁰Ne, ²²Ne, ²⁴Mg, ²⁶Mg and ²⁸Si were measured via the reorientation effect observed in Coulomb excitation with beams of ³²S, ³⁴S and ³⁷Cl ions. The quadrupole moments were deduced from the Dopplerbroadened γ-ray lineshapes observed at 0° with respect to the beam by means of a Ge(Li) detector. The results are: $Q(^{20} Ne, 2^{+}) = −0.23±0.08 e· b, Q(^{22} Ne, 2^{+}) = −0.18±0.04 e· b, Q(^{24} Mg, 2^{+}) = −0.24±0.06 e· b, Q(^{26} Mg, 2^{+}) = −0.16±0.04 e· b (−0.12±0.04 e· b), and Q(^{28} Si, 2^{+}) = +0.17±0.05 e· b$ . Two values are quoted for ²⁶Mg corresponding to the two possible signs of an interference term arising from virtual excitations through the second excited 2⁺ state of ²⁶Mg. A detailed description of the experimental technique and analysis is given, including the procedure whereby the semi-classical analysis of experimental lineshapes is modified to accord with a full quantal treatment of Coulomb excitation. Perturbing effects due to virtual E1 excitations and deorientation effects are calculated and found to be small.

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Physics Letters B

Abstract

References (11)

Phys. Rev. Letters

Ph. D. Thesis

Cited by (36)

Measurement of the average l ionization probability of gold in 25 MeV iodine-gold collisions

A study of <sup>22</sup>Ne with the <sup>20</sup>Ne(t, p) reaction

Antipairing and antistretching in <sup>22</sup>Ne

Quadrupole moments of nuclear excited states measured by the reorientation effect in coulomb excitation

Quadrupole moments of nuclear excited states measured by the reorientation effect in coulomb excitation

Reorientation measurements using the doppler-shift method: static quadrupole moments of <sup>20</sup>Ne, <sup>22</sup>Ne, <sup>24</sup>Mg, <sup>26</sup>Mg and <sup>28</sup>Si