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Effects of internal degrees of freedom on the heavy-ion fusion cross section

  • N. Takigawaf
Conference paper
Part of the Lecture Notes in Physics book series (LNP, volume 219)

Abstract

The large enhancement of the sub-barrier fusion cross section observed in a number of mediate-mass heavy ion collisions has been attributed to the effects of coupling of the relative motion to internal degrees of freedom. In this connection, I discuss several aspects of the tunnelling using the influence functional method. I first discuss the properties of the potential renormalization caused by a linear oscillator coupling, showing that in certain limits it has significant energydependence. Then, I discuss a factorization property of the influence functional when several internal modes of excitation are simultaneously involved, showing that there is a saturation effect in the enhancement of the transmission probability. Then, I show that the transmission probability can be factorized as a product of the adiabatic transmission probability and a dissipation factor if the relative motion couples to harmonic oscillators with high frequency. It is suggested that quite different correlations between the dissipation factor and the friction coefficient for a classically accessible process arises depending on the properties of the Hamiltonian of the internal coordinates. Finally, I show that a strong and localized coupling around the potential barrier yields a resonant fusion excitation function.

Keywords

Friction Coefficient Potential Barrier Harmonic Oscillator Transmission Probability Strength Distribution 
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Copyright information

© Springer-Verlag 1985

Authors and Affiliations

  • N. Takigawaf
    • 1
  1. 1.National Superconducting Cyclotron Laboratory and Department of Physics and AstronomyMichigan State UniversityEast Lansing48824

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