Eur. Phys. J. A (2013) 49: 63
https://doi.org/10.1140/epja/i2013-13063-2

Regular Article - Experimental Physics

Fusion of ⁶⁰Ni + ¹⁰⁰Mo near and below the Coulomb barrier

Multi-phonon and transfer couplings down to the hindrance region

¹⁹⁸⁹³ Laboratori Nazionali di Legnaro, INFN, I-35020, Legnaro (Padova), Italy
²⁹⁸⁹³ Dipartimento di Fisica e Astronomia, Università di Padova, and INFN, Sezione di Padova, I-35131, Padova, Italy
³⁹⁸⁹³ Physics Division, Argonne National Laboratory, 9700 S. Cass Avenue, 60439, Argonne, IL, USA
⁴⁹⁸⁹³ Department of Physics and Astronomy, Louisiana State University, 70803, Baton Rouge, LA, USA
⁵⁹⁸⁹³ University of Notre Dame, 46556, Notre Dame, IN, USA
⁶⁹⁸⁹³ Fermi National Accelerator Laboratory, 60510, Batavia, IL, USA
⁷⁹⁸⁹³ Lawrence Livermore National Laboratory, 94550, Livemore, CA, USA
⁸⁹⁸⁹³ University of Chicago, 60637, Chicago, IL, USA

^* e-mail: stefanini@lnl.infn.it

Received: 23 April 2013
Revised: 3 May 2013
Accepted: 10 May 2013
Published online: 27 May 2013

Abstract

The fusion excitation function of ⁶⁰ Ni + ¹⁰⁰ Mo has been measured from above the Coulomb barrier down to a cross section around 2 μb, looking for coupling and hindrance effects in this soft medium-mass system with positive Q-values for several neutron transfer channels. A comparison is made with previous results for ⁶⁴ Ni + ¹⁰⁰ Mo where no Q > 0 transfer channels exist and the hindrance effect is quite clear. The two excitation functions are very similar, as well as the corresponding logarithmic derivatives showing analogous saturations below the barrier. It appears that transfer couplings to Q > 0 channels seem to play a marginal role near and below the barrier for ⁶⁰ Ni + ¹⁰⁰ Mo , even if measurements of cross sections lower than 1 μb would be needed also for this system. Coupled-channels calculations confirm these observations and indicate that multi-phonon excitations dominate the fusion dynamics in the whole measured energy range.