Extreme nuclear shapes examined via giant dipole resonance lineshapes in hot light-mass systems

Abstract

The influence of alpha clustering on nuclear reaction dynamics is investigated using the giant dipole resonance (GDR) lineshape studies in the reactions 20 Ne (E lab =145,160 MeV) + 12 C and 20 Ne (E lab =160 MeV) + 27 Al , populating 32 S and 47 V, respectively. The GDR lineshapes from the two systems are remarkably different from each other. Whereas, the non alpha-like 47 V undergoes Jacobi shape transition and matches exceptionally well with the theoretical GDR lineshape estimated under the framework rotating liquid drop model (RLDM) and thermal shape fluctuation model (TSFM) signifying shape equilibration, for alpha cluster 32 S an extended prolate kind of shape is observed. This unusual deformation, seen directly via γ-decay for the first time, is predicted to be due to the formation of orbiting di-nuclear configuration or molecular structure of 16 O+ 16 O in 32 S superdeformed band.

Cluster formations in deformed states forSi28andS32Ichikawa1, Kanada-En’yo2, Möller3 2011Phys. Rev. C299730View full textAdd to dashboardCite

“…After such extension, the Jacobi shape transitions in the β-γ deformation space, as shown in Ref. [9], could be studied.…”

“…Many experimental searches for, and studies of such states have been performed [9,10]. An important feature of nuclear structure in the s-d shell region is that the densities of stronglydeformed one-body states often exhibit significant cluster structure [11,12], similar to the 16 O+ 16 O configuration suggested to exist in 32 S [7,13,14].…”

Deformation in28Si*produced via the16O+Kundu1, Bhattacharya2, Bhattacharya3 et al. 2013Phys. Rev. CSelf Cite

“…However, the present models are too simplistic to predict the actual deformation of the CN; more realistic event-by-event Monte Carlo calculations, taking into account the initial deformation, spin distribution of the CN and their subsequent evolutions, should be performed to have a proper understanding of the CN deformation. In addition, new experimental inputs (such as measurement of deformation from GDR studies [43]) are needed for a more comprehensive understanding of the process.…”

Exclusive giant dipole resonance measurement on the Jacobi transition in the19F+27Al system

“…The lowest component was interpreted to be due to the vibration along the most elongated axis of the highly deformed nuclei and further shifted downward due to the Coriolis splitting. In a recent experiment [5], which was also an essentially inclusive measurement, high-energy γ rays were measured in a 20 Ne + 27 Al reaction populating the CN 47 V at E X ∼ 108 MeV and in the J range up to ∼38. The authors report a GDR strength function with a low-energy component at ∼10 MeV and higher energy components up to ∼27 MeV.…”

“…In the inclusive measurements [3,5], a contribution from the noncompound nuclear reactions cannot be ruled out experimentally. The exclusive measurement reported in Ref.…”