Role of anharmonicities and non-linearities in heavy ion collisions. A microscopic approach

Abstract

Using a microscopic approach beyond RPA to treat anharmonicities, we mix two-phonon states among themselves and with one-phonon states. We also introduce non-linear terms in the external field. These non-linear terms and the anharmonicities are not taken into account in the "standard" multiphonon picture. Within this framework we calculate Coulomb excitation of 208Pb and 40Ca by a 208Pb nucleus at 641 and 1000MeV/A. We show with different examples the importance of the non-linearities and anharmonicities for the excitation cross section. We find an increase of 10 % for 208Pb and 20 % for 40Ca of the excitation cross section corresponding to the energy region of the double giant dipole resonance with respect to the "standard" calculation. We also find important effects in the low energy region. The predicted cross section in the DGDR region is found to be rather close to the experimental observation.

33 pages, 9 figures, uses epsfig.sty and espart.sty

References in corpus (2)

• Theory of Multiphonon Excitation in Heavy-Ion Collisions
• Quenching of $1^{+}$ excitations in the double giant resonance

Cited by in corpus (24)

• Microscopic Studies on Two-Phonon Giant Resonances
• Non-Linear Vibrations in Nuclei
• Anharmonic properties of double giant dipole resonance
• Excitation of nuclear anharmonic vibrations in heavy-ion fusion reactions
• Role of anharmonicities of nuclear vibrations in fusion reactions at subbarrier energies
• Towards a Microscopic Reaction Description Based on Energy-Density-Functional Structure Models
• Multiphonon Giant Resonances
• Microscopic calculations of double and triple Giant Resonance excitation in heavy ion collisions
• Anharmonic vibrations in nuclei
• Boson expansion methods applied to a two-level model in the study of multiple giant resonances
• Microscopic description of Coulomb and nuclear excitation of multiphonon states in ${}^{40}$Ca + ${}^{40}$Ca collisions
• Anharmonic collective excitation in a solvable model
• Coulomb Excitation of Double Giant Dipole Resonances
• Two-phonon background for the double giant resonance
• Comparison of exact and approximate cross-sections in relativistic Coulomb excitation
• Random matrix analysis of the monopole strength distribution in ${}^{208}$Pb
• On the Excitation of Double Giant Resonances in Heavy Ion Reactions
• Gauge dependence of calculations in relativistic Coulomb excitation
• Double giant resonances in deformed nuclei
• Isospin structure of one- and two-phonon GDR excitations
• Equivalence of the long-wavelength approximation and the truncated Taylor expansion in relativistic Coulomb excitation
• Excitation of multiple giant dipole resonances: from spherical to deformed nuclei
• Quantum derivation of the use of classical electromagnetic potentials in relativistic Coulomb excitation
• Event generator to construct cross sections for the multiphonon excitation of a set of collective vibrational modes