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Jacques Raynal provided two powerful tools to the nuclear reaction community interested in scattering processes, namely the ECISxx and DWBAxx computer codes (xx standing for the version year), which are renowned for both their numerical efficiency and the numerous applications they cover. The purpose of this work is twofold. First, it extends the possibilities of calculation of microscopic optical and transition potentials compared to what is proposed in the DWBA code. Then, following previous work by Arellano [Phys Rev C 76:014616, 2007], we develop a method to deal with coupled-channel calculations with non-local ingredients. Both codes DWBA and ECIS, and numerous past discussions with their author, offered guidance to elaborate and to validate new results focusing on neutron scattering off spin-0 target. Special attention has been paid to match the numerical precision of J. Raynal's tools. This was made possible by using a specific quadrature method for numerical integrations of functions with discontinuous derivatives. [ABSTRACT FROM AUTHOR]

The purpose of this study is to improve the modeling of nucleon direct inelastic scattering to the continuum using a microscopic and parameter-free approach. For the first time, direct elastic scattering, inelastic scattering to discrete excitations and to the continuum are described within a microscopic approach without adjustable parameters. Proton scattering off Zr and Pb are the reactions used as test case examples of the calculations. The model uses the Melbourne g-matrix and the Random Phase Approximation description of nuclear states, implemented with the Gogny D1S interaction. The relevant optical and transition potentials in a finite nucleus are calculated within a local density approximation. As we use the nuclear matter approach we limit our study to incident energies above 40 MeV. We first checked that this model provides an accurate account of measured cross sections for elastic scattering and inelastic scattering to discrete states. It is then applied to the direct inelastic scattering to the continuum considering all one-phonon excitations predicted within the RPA approach. This accounts for a part of the direct pre-equilibrium emission, often labeled as the one-step direct process in quantum-based approaches. Our approach provides a very accurate description of angular distributions where the one-step process dominates. The impact of collective excitations is shown to be non negligible for energy transfer to the target up to 20 MeV, decreasing as the incident energy increases. For incident energies above 80 MeV, our modeling provides a good account of direct proton emission for an energy transfer to the target up to 30 MeV. However, the proton emission we predict underestimates the measured cross sections for incident energies below 80 MeV. We compare our prediction to those of the phenomenological exciton model to help interpret this result. Directions that may improve our modeling are discussed. [ABSTRACT FROM AUTHOR]

Abstract: Differential cross sections from fully microscopic calculations of inelastic proton scattering off 208Pb are compared to experimental scattering data for incident proton energies between 65 and 201 MeV. The required nucleon–nucleus interactions were formed by folding nuclear structure information with a reliable nucleon–nucleon effective interaction that has no adjustable parameter. The absence of phenomenological normalisation in our approach offers the possibility to interpret with confidence the calculated results in terms of the quality of the underlying nuclear structure description: a feature that had been reserved, until recently, to the electron probe. We have used this method to investigate the effect of long range correlations embedded in excited states on calculated inelastic observables and demonstrate the sensitivity of nucleon scattering predictions to details of the nuclear structure. [Copyright &y& Elsevier]

A microscopic calculation of reaction cross sections for nucleon-nucleus scattering has been performed by explicitly coupling the elastic channel to all particle-hole excitations in the target and one-nucleon pickup channels. The particle-hole states may be regarded as doorway states through which the flux flows to more complicated configurations, and subsequently to long-lived compound nucleus resonances. Target excitations for 40,48Ca, 58Ni,90Zr, and 144Sm were described in a random-phase framework using a Skyrme functional. Reaction cross sections obtained agree very well with experimental data and predictions of a state-of-the-art fitted optical potential. Couplings between inelastic states were found to be negligible, while the pickup channels contribute significantly. The effect of resonances from higher-order channels was assessed. Elastic angular distributions were also calculated within the same method, achieving good agreement with experimental data. Observed absorptions are completely accounted for by explicit channel coupling, for incident energies between 10 and 70 MeV, with consistent angular distribution results. [ABSTRACT FROM AUTHOR]