Classical dynamical modelling of near-barrier breakup

Abstract

Abstract. The complete fusion of light, weakly-bound nuclides is known to be significantly suppressed with respect to comparable well-bound projectiles or with respect to single barrier penetration model calculations. Strong α-clustering in these light systems mean that they very easily disintegrate into clusters, either via direct excitation of their intrinsic cluster continuum, or via transfer reactions which connect to unbound states in neighbouring nuclides. This breakup is thought to reduce the probability for complete fusion. Here we discuss which processes cause breakup, whether or not breakup happens fast enough, and the interpretation of measurements made at the Australian National University of breakup using classical dynamical models. Understanding the intimate details of breakup, and the resonances through which it proceeds, will be crucial in determining its likely influence on fusion.

Origins of Incomplete Fusion Products and the Suppression of Complete Fusion in Reactions of Li7

“…The idea that breakup capture should peak backward of no-capture breakup is confirmed by classical dynamical model simulations of breakup [24]. The simulation was constrained to reproduce the individual no-capture breakup total cross sections (σ αα , σ αt , σ αd , σ αp ) as well as the measured relative energy distributions of the breakup fragments [20,21,28].…”

“…The amount of breakup capture occurring at abovebarrier energies can then be estimated using classical trajectory models [23,24]. Some works have suggested that breakup capture fully accounts for the suppression of complete fusion [19,25,26].…”

“…To overcome kinematic bias, double-differential cross sections d 2 σ=dEdΩ for α arising from no-capture breakup were extracted using the efficiency correction procedure described in Ref. [29] using a classical dynamical model simulation [24] for each breakup mode [30]. At E c:m: ¼ 38.72 MeV, the no-capture breakup cross section of 36 AE 1 mb comprises almost equal components of direct breakup Li → α þ t (σ αt ¼ 9.6 AE 0.6 mb), and breakup following one proton pickup…”