HAL : in2p3-00257541, version 1
 arXiv : 0802.1687
 Low-lying dipole resonance in neutron-rich Ne isotopes
 (2008)
 Microscopic structure of the low-lying isovector dipole excitation mode in neutron-rich $^{26,28,30}$Ne is investigated by performing deformed quasiparticle-random-phase-approximation (QRPA) calculations. The particle-hole residual interaction is derived from a Skyrme force through a Landau-Migdal approximation. We have obtained the low-lying resonance in $^{26}$Ne at around 8.5 MeV. It is found that the isovector dipole strength at $E_{x}<10$ MeV exhausts about 6.0% of the classical Thomas-Reiche-Kuhn dipole sum rule. This excitation mode is composed of several QRPA eigenmodes, one is generated by a $\nu(2s^{-1}_{1/2} 2p_{3/2})$ transition dominantly, and the other mostly by a $\nu(2s^{-1}_{1/2} 2p_{1/2})$ transition. The neutron excitations take place outside of the nuclear surface reflecting the spatially extended structure of the $2s_{1/2}$ wave function. In $^{30}$Ne, the deformation splitting of the giant resonance is large, and the low-lying resonance is overlapping with the giant resonance.
 Thème(s) : Physique/Physique Nucléaire Théorique
 Lien vers le texte intégral : http://fr.arXiv.org/abs/0802.1687
 in2p3-00257541, version 1 http://hal.in2p3.fr/in2p3-00257541 oai:hal.in2p3.fr:in2p3-00257541 Contributeur : Suzanne Robert <> Soumis le : Mardi 19 Février 2008, 16:01:16 Dernière modification le : Mardi 19 Février 2008, 16:11:22