Channel coupling effects on the fusion excitation functions for {sup 28}Si+{sup 90,94}Zr in sub- and near-barrier regions

Journal Article · Thu Apr 15 00:00:00 EDT 2010 · Physical Review. C, Nuclear Physics

DOI:https://doi.org/10.1103/PHYSREVC.81.044610· OSTI ID:21388941

Kalkal, Sunil; Mandal, S; Verma, Shashi; Saxena, Mansi; Goyal, Savi; Siwal, Davinder; Garg, Ritika; Kumar, Suresh; Singh, R ^[1]; Madhavan, N; Jhingan, A; Nath, S; Gehlot, J; Varughese, T; Golda, K S; Muralithar, S ^[2]; Prasad, E ^[3]; Sandal, Rohit; Behera, B R ^[4]; Pramanik, U D ^[5]

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1. Department of Physics and Astrophysics, University of Delhi, Delhi-110007 (India)
2. Inter University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi-110067 (India)
3. Department of Physics, Calicut University, Calicut-673635 (India)
4. Department of Physics, Panjab University, Chandigarh-160014 (India)
5. Saha Institute of Nuclear Physics, 1/AF Bidhan Nagar, Kolkata-700064 (India)

Fusion excitation functions and angular distributions of evaporation residues (ERs) have been measured for {sup 28}Si+{sup 90,94}Zr systems around the Coulomb barrier using the recoil mass spectrometer, Heavy Ion Reaction Analyzer (HIRA). For both systems, the experimental fusion cross sections are strongly enhanced compared to the predictions of the one-dimensional barrier penetration model (1-d BPM) below the barrier. Coupled channels formalism has been employed to theoretically explain the observed sub-barrier fusion cross section enhancement. The enhancement could be explained by considering the coupling of the low-lying inelastic states of the projectile and target in the {sup 28}Si+{sup 90}Zr system. In the sub-barrier region, the measured fusion cross sections for {sup 28}Si+{sup 94}Zr turned out to be about an order of magnitude higher than the ones for the {sup 28}Si+{sup 90}Zr system, which could not be explained by coupling to inelastic states alone. This observation indicates the importance of multinucleon transfer reaction channels with positive Q values in the sub-barrier fusion cross section enhancement, because {sup 90,94}Zr are believed to have similar collective strengths. This implies that no strong isotopic dependence of fusion cross sections is expected as far as the couplings to collective inelastic states are concerned. In addition, the role of projectile and multiphonon couplings in the enhancement has been explored.

• OSTI ID: 21388941
• Journal Information: Physical Review. C, Nuclear Physics, Vol. 81, Issue 4; Other Information: DOI: 10.1103/PhysRevC.81.044610; (c) 2010 The American Physical Society; ISSN 0556-2813
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ANGULAR DISTRIBUTION
COULOMB FIELD
COUPLED CHANNEL THEORY
COUPLING
EVAPORATION
EXCITATION FUNCTIONS
FORECASTING
HEAVY ION REACTIONS
MASS SPECTROMETERS
MULTI-NUCLEON TRANSFER REACTIONS
ONE-DIMENSIONAL CALCULATIONS
PROJECTILES
RECOILS
RESIDUES
SILICON 28
THERMONUCLEAR REACTIONS
ZIRCONIUM 90
ZIRCONIUM 94
CROSS SECTIONS
DIFFERENTIAL CROSS SECTIONS
DIRECT REACTIONS
DISTRIBUTION
ELECTRIC FIELDS
EVEN-EVEN NUCLEI
FUNCTIONS
INTERMEDIATE MASS NUCLEI
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
LIGHT NUCLEI
MEASURING INSTRUMENTS
MILLISECONDS LIVING RADIOISOTOPES
NUCLEAR REACTIONS
NUCLEI
NUCLEOSYNTHESIS
PHASE TRANSFORMATIONS
RADIOISOTOPES
SILICON ISOTOPES
SPECTROMETERS
STABLE ISOTOPES
SYNTHESIS
TRANSFER REACTIONS
ZIRCONIUM ISOTOPES