Studies of continuum coupling effects in Li-6(alpha,alpha) and Li-6(p,p') excitation

The nonresonant continuum part of Li-6 double right arrow alpha + d breakup at low relative fragment energies, induced by 50 MeV alpha-particle and 65 MeV proton scattering, is discretized in two separate energy bins. Realistic coupled-channel analyses are carried out, coupling the 1(+) ground state with both the resonant 3(1+) state as well as the two nonresonant discretized continuum states, including selfcoupling. A simultaneous fit to the data puts stringent constraints on the coupling strengths. It delineates that their arbitrary variation is unacceptable and that the complex coupling schemes in CDCC calculations need sufficient experimental control. The coupling effects by multistep processes (virtual excitations) through intermediate continuum states prove to be marginal in the considered Li-6(alpha, alpha')Li-6* and 6Li(p,p')Li-6* cases.