Quasifree mechanism in theLi6+Li6→3αreaction at low energy

Abstract

The 6 Li + 6 Li → 3α reaction was measured in a kinematically complete experiment at 3.1 and 2.5 MeV to investigate the presence of quasifree processes at sub-Coulomb energies. Results from the present experiment show a very clear evidence of quasifree mechanisms with an α-particle spectator either in the target or in the projectile. To check the occurrence of quasifree processes, "energy sharing" and "angular correlation" analyses have been performed in the framework of the plane wave impulse approximation, both leading to consistent results. The huge peak in the angular correlation spectra, previously ascribed to the "anomalous quasifree" process, corresponds instead to the population of the 22.2-MeV (2 + , = 800 keV) state of 8 Be.

Nuclear clustering and the electron screening puzzle

“…Moreover, if the deuterons within the 6 Li nuclei approach each other and directly fuse to α particles, it would increase enormously the cross section for the reaction, as shown in Figure 1. That is what one observes with the cross section for 6 Li + 6 Li → 3α [10][11][12][13][14]. It is likely that the deuterons within 6 Li tunnel through the barrier individually to form the α-particles, leaving the other two α-particles behind.…”

Strong screening effects on resonant nuclear reaction23Mg (p, γ)24Al in the surface of magnetars

“…Following the works of Fushiki et al (1989), we will reinvestigate the electron Fermi energy in SMFs, and derived new results for SES theory and the screening rates for nuclear reaction in SMFs, based on the Thomas-Fermi-Dirac approximations. Secondly, our discussions also differs from that of Spitaleri & Bertulani (2015), which analyzed the influence of the SES only in the case without SMFs. Finally, Potekhin, & Chabrier, (2013) also discussed the electron screening effect on stellar thermonuclear Fusion.…”

“…The related discussions were provided by Liolios et al (2000), Liolios et al (2001), Kravchuk et al (2014) and Liu (2013). Very recently, Spitaleri & Bertulani (2015) also discussed the electron screening and nuclear clustering puzzle. Their results show that the large screening potential values is in fact due to clusterization effects in nuclear reactions, especially in reaction involving light nuclei.…”

The electron screening puzzle and nuclear clustering

“…Thus, even if the spectroscopic amplitudes are small, the cluster-like configuration enhances the cross section by many orders of magnitude, more than compensating the small configuration probability, also related to the preformation factor. The experimental data clearly shows that the fusion cross section in the 6 Li + 6 Li → 3α does not decrease as fast with energy as the penetrability for 6 Li + 6 Li channel does [8][9][10][11][12]. An additional effect might be responsible for an even larger enhancement of the cross section.…”