The energy dependence of the nucleon - nucleus potential

Mackintosh, R. S.; Cooper, S.G.

doi:10.1088/0954-3899/23/5/009

Cited by 21 publications

(39 citation statements)

References 14 publications

(25 reference statements)

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“…In particular, we have determined [11] the energy-dependent local potential that represents the Perey Buck non-local potential and verified that its energy dependence agrees well with that derived from RGM (see below) and also the phenomenological energy dependence.…”

Section: Local Equivalent Potentialssupporting

confidence: 77%

Scanning Tunnelling Microscopy on Ultrathin Organic Layers of Phthalocyanine and Naphthalocyanines on Highly Oriented Pyrolytic Graphite (0001)

Gopakumar

Lackinger

Hietschold

2006

jjap

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It is now straightforward to carry out S-matrix to potential inversion over a very wide range of energies and for a wide range of projectile-target combinations. Inversion is possible in many cases involving spin. Iterative perturbative inversion also permits direct scattering data-to-potential inversion and furnishes powerful tools for the phenomenological analysis of nuclear scattering. The resulting single particle potentials exhibit various generic properties which challenge fundamental reaction theories as well as yield information on densities, provide input for reaction calculations. S-matrix-to-potential inversion is also a powerful tool for directly investigating theoretical processes which contribute to internuclear potentials. Various studies have given insight into contributions to the dynamic polarization potential that are due to breakup processes and/or collective and reaction channel coupling and have also illuminated the role played by exchange processes in leading to non-locality and parity dependence of the potentials. A case study involving d + 4 He is a model for ways in which inversion applied jointly to theory and experiment might illuminate the scattering of exotic nuclei.

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Section: Local Equivalent Potentialssupporting

confidence: 77%

Scanning Tunnelling Microscopy on Ultrathin Organic Layers of Phthalocyanine and Naphthalocyanines on Highly Oriented Pyrolytic Graphite (0001)

Gopakumar

Lackinger

Hietschold

2006

jjap

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“…The most widely discussed form of nonlocality, that which is due to knock-on exchange and which is phenomenologically represented by the Perey Buck form [14], apparently gives rise to no substantial undularity, see Ref. [15]. This exchange nonlocality is quite distinct from, and additional to, dynamical nonlocality arising from channel coupling, as discussed in Ref.…”

Section: Introductionmentioning

confidence: 94%

Evidence forL-dependence generated by channel coupling:O16scattering fromC12
Mackintosh
¹

2016
Phys. Rev. C
8
2
32
0
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Background:In earlier work, inversion of S matrix for 330 MeV 16 O on 12 C resulted in highly undulatory potentials; the S matrix resulted from the inclusion of strong coupling to states of projectile and target nuclei. L-independent S-matrix equivalent potentials for other explicitly L-dependent potentials have been found to be undulatory. Purpose: To investigate the possible implications of the undulatory dynamic polarization potential for an underlying L dependence of the 16 O on 12 C optical potential. Methods: S matrix to potential, S L → V (r), inversion which yields local potentials that reproduce the elastic channel S matrix of coupled channel (CC) calculations, will be applied to the S matrix for 115.9 MeV 16 O on 12 C. Further, S L for explicitly L-dependent potentials are inverted and the resulting L-independent potentials are characterized and compared with the undulatory potentials found for 16 O on 12 C. Results: Some of the undulatory features exhibited by the potentials modified by channel coupling for 115.9 MeV 16 O on 12 C can be simulated by simple parameterized L-dependent potentials. Conclusions:The elastic scattering of 16 O by 12 C is a particularly favorable case for revealing the effective L dependence of the potential modified by channel coupling. Nevertheless, there is no reason to suppose that undularity is not a generic property leading in many cases to the choice: nucleus-nucleus potentials are (i) smooth and L-dependent, (ii) L-independent and undulatory, or (iii) both.

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“…This dynamical nonlocality is unrelated to exchange nonlocality that generates most of the energy dependence of the nucleon OMP and is responsible for the well-known Perey effect; see Refs. [25,26]. The cases in Table III reveal consequences of the underlying nonlocality such as the different degrees of departure of the real and imaginary DPPs and their volume integrals from the proportionality to deformation length squared, δ 2 , that would be expected for the formal nonlocal DPP for phonon coupling.…”

Section: More General Vibrational Couplingmentioning

confidence: 99%

Phonon coupling effects in proton scattering fromCa40

Mackintosh

Keeley

2014

Phys. Rev. C

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Background: Formal optical model theory shows that coupling to vibrational nuclear states generates a nonlocal and l-dependent dynamical polarization potential (DPP). Little is established concerning the DPP, yet its properties are crucial for explaining the departures of optical model potentials (OMPs) from global behavior and for the rigorous extraction of spectroscopic information from direct reactions. Purpose: To appraise the application of channel coupling followed by S-matrix inversion for the systematic exploration of the contribution of the coupling of collective states to the nucleon OMP and to identify properties of nuclear potentials indicative of l-dependence. Methods: S-matrix to potential, S lj → V (r) + l · s V SO (r), inversion provides local potentials that precisely reproduce the elastic channel S-matrix from coupled channel (CC) calculations. Subtracting the elastic channel uncoupled (bare) potential yields a local and l-independent representation of the DPP. The dependence of this local DPP upon the nature of the coupled states and upon other parameters can be studied. Results: All components of the DPP arising from coupling to vibrational states are substantially undulatory with a point-by-point magnitude therefore disproportionate to their contribution to volume integrals. Information relating to dynamical nonlocality is found. The proton charge leads to a substantial difference between DPPs for protons and neutrons. Conclusions: Undulatory features in potentials found in precision fits to elastic scattering data are significant, are a consequence of coupling to inelastic channels and must be allowed for in phenomenology; they are indirect evidence of l-dependence. Within the model, coupling to excited states magnifies the effect of the proton charge on the difference between proton-nucleus and neutron-nucleus interactions. Coupled channel plus inversion is a procedure of wide applicability, complementary to evaluation of the Feshbach formalism.

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The energy dependence of the nucleon - nucleus potential

Abstract: By way of evaluating a new procedure for energy-dependent inversion we have compared the energy dependence of the local potential phase equivalent to the Perey-Buck non-local potential with the energy dependence of local potentials derived from RGM and phenomenology.

Cited by 21 publications

References 14 publications

Scanning Tunnelling Microscopy on Ultrathin Organic Layers of Phthalocyanine and Naphthalocyanines on Highly Oriented Pyrolytic Graphite (0001)

Scanning Tunnelling Microscopy on Ultrathin Organic Layers of Phthalocyanine and Naphthalocyanines on Highly Oriented Pyrolytic Graphite (0001)

Evidence forL-dependence generated by channel coupling:O16scattering fromC12
Mackintosh
¹

2016
Phys. Rev. C
8
2
32
0
View full text Add to dashboard Cite

Phonon coupling effects in proton scattering fromCa40

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The energy dependence of the nucleon - nucleus potential

Abstract: By way of evaluating a new procedure for energy-dependent inversion we have compared the energy dependence of the local potential phase equivalent to the Perey-Buck non-local potential with the energy dependence of local potentials derived from RGM and phenomenology.

Cited by 21 publications

References 14 publications

Scanning Tunnelling Microscopy on Ultrathin Organic Layers of Phthalocyanine and Naphthalocyanines on Highly Oriented Pyrolytic Graphite (0001)

Scanning Tunnelling Microscopy on Ultrathin Organic Layers of Phthalocyanine and Naphthalocyanines on Highly Oriented Pyrolytic Graphite (0001)

Evidence forL-dependence generated by channel coupling:O16scattering fromC12Mackintosh1 2016Phys. Rev. C82320View full textAdd to dashboardCite

Phonon coupling effects in proton scattering fromCa40

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About

Evidence forL-dependence generated by channel coupling:O16scattering fromC12
Mackintosh
¹

2016
Phys. Rev. C
8
2
32
0
View full text Add to dashboard Cite