Role of deformation on giant resonances within the quasiparticle random-phase approximation and the Gogny force

Fully consistent axially-symmetric-deformed quasiparticle random phase approximation (QRPA) calculations have been performed, in which the same Gogny D1S effective force has been used for both the Hartree-Fock-Bogolyubov mean field and the QRPA approaches. Giant resonances calculated in deformed ${}^{26-28}\mathrm{Si}$ and ${}^{22-24}\mathrm{Mg}$ nuclei as well as in the spherical ${}^{30}\mathrm{Si}$ and ${}^{28}\mathrm{Mg}$ isotopes are presented. Theoretical results for isovector-dipole and isoscalar monopole, quadrupole, and octupole responses are presented and the impact of the intrinsic nuclear deformation is discussed.

Figure 1

HFB potential energy curves $V$ as functions of the axial deformation parameter β for ${}^{26-30}\mathrm{Si}$ and ${}^{22-28}\mathrm{Mg}$.

Figure 2

Neutron (full lines) and proton (dashed lines) pairing energies $E_p$ as functions of axial deformation parameter β in ${}^{26-30}\mathrm{Si}$ and ${}^{22-28}\mathrm{Mg}$.

Figure 3

Fractions of the isovector dipole EWSR in ${}^{22-28}\mathrm{Mg}$ and ${}^{26-30}\mathrm{Si}$. In deformed nuclei, $K^{\pi }=0^{-}$ and $\left|K\right|{}^{\pi }=1^{-}$ components are indicated in black and green, respectively.

Figure 4

Fractions of the monopole EWSR in ${}^{22-28}\mathrm{Mg}$ and ${}^{26-30}\mathrm{Si}$.

Figure 5

Fractions of the quadrupole EWSR in ${}^{22-28}\mathrm{Mg}$ and in ${}^{26-30}\mathrm{Si}$. In the deformed nuclei, $K^{\pi }=0^{+},\left|K\right|{}^{\pi }=1^{+}$, and $\left|K\right|{}^{\pi }=2^{+}$ components are indicated in black, green, and purple, respectively. Blue curves are obtained from folding of QRPA spectra with a Lorentzian distribution.

Figure 6

Fractions of the octupole EWSR in ${}^{22-28}\mathrm{Mg}$ and ${}^{26-30}\mathrm{Si}$. In the deformed nuclei, $K^{\pi }=0^{-},\left|K\right|{}^{\pi }=1^{-},\left|K\right|{}^{\pi }=2^{-}$, and $\left|K\right|{}^{\pi }=3^{-}$ components are indicated in black, green, purple, and red, respectively. Blue curves are obtained from folding of QRPA spectra with a Lorentzian distribution.