Isoscalar dipole excitations in ${}^{16}$O

Abstract

Isoscalar (IS) monopole and dipole excitations in ${}^{16}$O were investigated by the method of shifted basis antisymmetrized molecular dynamics combined with the generator coordinate method. Significant strengths of the IS monopole and dipole transitions were obtained in the low-energy region below the giant resonances. In addition to the compressive mode, which mainly contributes to the high-energy strengths for the IS dipole giant resonance, we obtained a variety of low-energy dipole modes such as the vortical dipole mode in the $1_1^{-}$ state of the vibrating tetrahedral $4\alpha$ and the ${}^{12}$C+$\alpha$ cluster structure in the $1_2^{-}$ state. The $1_1^{-}$ state contributes to the significant low-energy strength of the IS dipole transition as 5\% of the energy-weighted sum rule, which describes well the experimental data observed by the $\alpha$ inelastic scattering.

arXiv comment10 pages, 6 figures

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Cited by in corpus (10)

• Systematics of toroidal dipole modes in Ca, Ni, Zr, and Sn isotopes
• Microscopic calculation of inelastic proton scattering off ${}^{18}$O, ${}^{10}$Be, ${}^{12}$Be, and ${}^{16}$C for study of neutron excitation in neutron-rich nuclei
• Low-energy cluster vibrations in N = Z nuclei
• Isoscalar monopole and dipole transitions in ${}^{24}$Mg, ${}^{26}$Mg and ${}^{28}$Si
• Individual dipole toroidal states: main features and search in (e,e') reaction
• A variety of clustering in ${}^{18}$O
• Monopole and dipole transitions of the cluster states of 18O
• Cluster correlation and nuclear vorticity in low-lying $1^{-}$ states of ${}^{24}$Mg
• alpha+28Si and 16O+16O molecular states, and their isoscalar monopole strengths
• Low-energy dipole excitations in ${}^{20}$O with antisymmetrized molecular dynamics