Electric dipole strength in the deformed 144,146,148,150,152,154Nd nuclei

Abstract

The Giant Dipole and Pygmy Dipole strengths distributions in the chain of the double-even 144−154Nd nuclei were investigated using a translational and Galilean invariant quasiparticle random phase approximation (TGI-QRPA). Through the cross sections, transition probabilities and other properties, such as the splitting behaviors of the electric dipole response between the K=0 and K=±1 components of the electric dipole response were investigated. The predicted concentration of the Giant Dipole Resonance (GDR) exhausts than 99% of the energy weighed sum rules (EWSR) below 20 MeV. Where up to the energy 8 MeV the highly-fragmented E1 strength was predicted. The calculations revealed that neutron excess together with deformation significantly increases the total low-energy E1 strength, while when increasing the deformation, K=0 fills the Pygmy Dipole Resonance (PDR) region more strongly than K=±1. Here also through nucleon structures such as collectivity and isospin structure of the excitations were presented discussion on differences between PDR and GDR region for neodymium isotopes. In addition, our results reveal that the spin-flip M1 strengths exhibit a broad distribution between 5 and 8 MeV and occupy less than 8% of the total dipole strength in that energy region.