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)


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.


Friction Coefficient Potential Barrier Harmonic Oscillator Transmission Probability Strength Distribution 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. 1.
    U. Jahnke, et al., Phys. Rev. Lett. 48, 17 (1982).Google Scholar
  2. 2.
    N. Takigawa and G.F. Bertsch, Phys. Rev. C29, 2358 (1984).Google Scholar
  3. 3.
    N. Takigawa and A.B. Balantekin, MSU preprint, June 1984.Google Scholar
  4. 4.
    R. Broglia, invited talk at this conference.Google Scholar
  5. 5.
    S. Landowne, invited talk at this conference.Google Scholar
  6. 6.
    M. Rhoades-Brown, invited talk at this conference.Google Scholar
  7. 7.
    A.O. Caldeira and A.J. Leggett, Ann. Phys. 149, 374 (1983) and references therein.Google Scholar
  8. 8.
    A.O. Caldeira and A.J. Leggett, Phys. Rev. Lett. 46, 211 (1981).Google Scholar
  9. 9.
    A.B. Balantekin and N. Takigawa, Ann. Phys. in press.Google Scholar
  10. 10.
    S.Y. Lee, Phys. Rev. C29, 1932 (1984).Google Scholar
  11. 11.
    N. Takigawa, to be published in the Proc. of the Seventh Oaxtepec Symposium on Nuclear Physics, Mexico, 1984; and N. Takigawa and G.F. Bertsch, in preparation.Google Scholar
  12. 12.
    H. Esbensen, Nucl Phys. A352, 147 (1981).Google Scholar
  13. 13.
    W.H. Miller, Adv. Chem. Phys. 35, 69 (1974).Google Scholar
  14. 14.
    S. Coleman, Phys. Rev. D15, 2929 (1977); 16, 1248(E) (1977); C.G. Callan and S. Coleman, ibid. 16, 1762 (1977).Google Scholar
  15. 15.
    S.Y. Lee and N. Takigawa, Phys. Rev. C28, 1123 (1983).Google Scholar
  16. 16.
    D.M. Brink and U. Smilansky, Nucl. Phys. A405, 301 (1983).Google Scholar
  17. 17.
    L.C. Vaz, J.M. Alexander, M. Prakash, and S.Y. Lee, Proc. Int. Conf. on Nuclear Physics with Heavy Ions, Stony Brook, NY, April 1983; Vol. VI Nucl. Sci. Research Conf. Ser. (Harwood Academic Publishers, Amsterdam), p. 31.Google Scholar
  18. 18.
    A.B. Balantekin, S.E. Koonin, and J.W. Negele, Phys. Rev. C28, 1565 (1983); S. Koonin, invited talk at this conference.Google Scholar
  19. 19.
    A. Bohr and B.R. Mottelson, Nuclear Structure, Vol. I (Benjamin, New York, 1969) p. 302.Google Scholar
  20. 20.
    D.M. Brink, M.C. Nemes and D. Vautherin, Ann. Phys. (NY) 147, 171 (1983).Google Scholar
  21. 21.
    M. Beckerman, invited talk at this conference.Google Scholar
  22. 22.
    E.R. Cosman, C.E. Ordones and R.J. Ledoux, contribution to this conference.Google Scholar
  23. 23.
    B. Cujec, invited talk at this conference.Google Scholar
  24. 24.
    D.M. Brink, in “Progress in Particle and Nuclear Physics”, edited by D. Wilkinson (Pergamon, Oxford, 1981) Vol. IV, p. 323Google Scholar

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

Personalised recommendations