Monopole oscillations in light nuclei with a molecular dynamics approach

Abstract

Collective monopole vibrations are studied in the framework of an antisymmetrized version of molecular dynamics as a function of the vibration amplitude. The giant monopole resonance energy in 40 Ca is sensitive to the incompressibility of the effective interaction, in good agreement with complete time-dependent Hartree-Fock calculations. The collective response of 12 C, 16 O, and 24 Mg is also studied. For these lighter nuclei that have an important contribution of an α-clustered component, different frequencies are observed, corresponding to two different types of vibrations associated with breathing and moving of the underlying clusters. Possible connections with direct breakup into alpha clusters at high excitation energy are discussed.

Microscopic clustering in light nuclei

“…The lowering mechanism of the ISM strengths by the large amplitude cluster motion was also demonstrated in the time-dependent FMD calculation by Furuta et al (Furuta et al, 2010). In applications of time-dependent approaches to nuclear excitations, the response functions are calculated by the Fourier transform (frequency) of the time evolution of the system.…”

“…In structure studies the flexible treatment of the width parameters in the FMD is efficient, for example, for the neutron-halo structure of neutron-rich nuclei. The variation of width parameters in the time-dependent FMD is also effective in description of the giant monopole resonance (Furuta et al, 2010), whereas the giant resonances are described with superposition of shifted single-particle Gaussian wave packets in the sAMD framework.…”

Dipole oscillation modes in lightα-clustering nuclei

“…8 Be composed by two α particles, has a scarcely greater value than the threshold energy for the decay into two α particles [3]. For 12 C, triangular-like configuration, is predicted around the ground state by Fermionic molecular dynamics [26], anti-symmetrized molecular dynamics [27,28], and covariant density functional theory [29], which is supported by a recent experimental result [30]. A three-α linear-chain configuration was predicted as an excited state in time-dependent Hartree-Fock theory [12], and other different approaches [31].…”

Interplay between collision dynamics and nuclear matter properties from microscopic viewpoint

“…The same problem was studied by the fermionic molecular dynamics (FMD) as well [8], in which the width parameters of individual wave packets are treated as time-dependent variables as well as the centroid variables. In this case, the calculated result shows an oscillation pattern composed of two modes with different frequencies.…”

“…[8]. Figure 3 shows the dependence of the oscillation frequency on the amplitude or the excitation energy.…”