2007/06/03 by Ajit Kumar Mohanty, Mohanty, Ajit Kumar
Earth and Planetary Sciences · Physics and Astronomy · #Cold Fusion and Nuclear Reactions #FOS: Physical sciences #Nuclear Physics and Applications #Nuclear Theory (nucl-th) #Nuclear physics research studies #nucl-th
paper · pdf · doi:10.48550/arxiv.0706.0303
11 pages, 9 figures
openalex publication_date 2007/06/03 · arxiv created 2010/11/17 · arxiv updated 2010/11/18 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
A hybrid model where the tunneling probability is estimated based on both sudden and adiabatic approaches has been proposed to understand the heavy ion fusion phenomena at deep sub-barrier energies. It is shown that under certain approximations, it amounts to tunneling through two barriers: one while overcoming the normal Coulomb barrier (which is of sudden nature) along the radial direction until the repulsive core is reached and thereafter through an adiabatic barrier along the neck degree of freedom while making transition from a di-nuclear to a mono-nuclear regime through shape relaxation. A general feature of this hybrid model is a steep fall-off of the fusion cross section, sharp increase of logarithmic derivative L(E) with decreasing energy and the astrophysical S-factor showing a maxima at deep sub-barrier energies particularly for near symmetric systems. The model can explain the experimental fusion measurements for several systems ranging from near symmetric systems like 58Ni+64Ni, 58Ni+58Ni and 58Ni+69Y to asymmetric one like 16O+208Pb where the experimental findings are very surprising. Since the second tunneling is along the neck co-ordinate, it is further conjectured that deep sub-barrier fusion supression may not be observed for the fusion of highly asymmetric projectile target combinations where adiabatic transition occurs automatically without any hindrance. The recent deep sub-barrier fusion cross section measurements of 6Li+198Pt system supports this conjecture.