Quantum calculation of the barrier and internal wave contributions to light- and heavy-ion elastic scattering

Albinski, J.; Michel, F. C.

doi:10.1103/physrevc.25.213

Cited by 26 publications

(28 citation statements)

References 16 publications

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“…The Brink and Takigawa method looks almost identical to the one presented here and gives very similar results [15,16]. There is, however, an essential difference between the method presented here and that of Brink and Takigawa.…”

Section: Discussionsupporting

confidence: 80%

Coulomb amplitude representation and nuclear diffraction and refraction

Wojciechowski

2004

Can. J. Phys.

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A new, consistent with wave-optics, method of treating diffraction and refraction in nuclear elastic scattering, is proposed and discussed. The method is based on the decomposition of the total elastic-scattering amplitude, written in a different form than usual, into the amplitude describing pure diffraction, and the rest, i.e., refraction and reflection. It is shown that nuclear diffraction is due to incompleteness of the Coulomb-scattering amplitude and is described by it. It is show that diffraction can be regarded as a kind of "background" always present, irrespective of the system being studied. PACS Nos.: 24.10.Ht, 42.25.Fx, 42.25.GyRésumé : Nous proposons et analysons une nouvelle méthode, cohérente avec l'optique ondulatoire, pour décrire la diffraction et la réfraction dans la diffusion nucléaire élastique. La méthode est basée sur la décomposition de l'amplitude de diffusion élastique totale, écrite d'une façon différente, en une amplitude décrivant la diffraction pure et une autre amplitude qui comprend la réfraction et la réflexion. Nous montrons que la diffraction nucléaire est due à l'inachèvement de l'amplitude coulombien et est décrite par elle. Nous montrons que la diffraction peut être vue comme une sorte de bruit de fond toujours présent, indépendamment du système étudié.[Traduit par la Rédaction]

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Section: Discussionsupporting

confidence: 80%

Coulomb amplitude representation and nuclear diffraction and refraction

Wojciechowski

2004

Can. J. Phys.

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“…Still, at that time, the significance of this backward rise was overlooked, and the analysis of Bassani et al [21] concludes that " 6 Li behaves as a strongly absorbed projectile." These data are well described within the optical model (OM), if use is made of a moderate absorption; and a semiclassical decomposition of the elastic scattering amplitude into its so-called barrier-wave and internal-wave (B/I) contributions [22] confirmed later, in an unambiguous way [23], that the 6 Li + 16 O system displays a surprising transparency: Indeed, the backward enhancement is completely dominated by that part of the incident flux that crosses the potential barrier and reemerges in the elastic channel after penetrating the nuclear interior. In fact the transparency of the system is so high that in the 29.8-MeV 16 O( 6 Li, 6 Li) angular distribution the influence of the internalwave component can be felt at angles as small as 50 • !…”

Section: Introductionmentioning

confidence: 69%

“…More direct evidence for the transparency of the system is provided by the barrier-wave/internal-wave decomposition of the scattering amplitude, which separates cleanly the two interfering components of the amplitude responsible for the Airy structure [14,15]. Although this approach was initially introduced within a semiclassical context [22], it is in most cases possible to avoid the difficult semiclassical calculations and to perform the B/I decomposition using an ordinary OM code [23]. The barrier-wave and internal-wave components of the amplitude have an intuitively very simple meaning: They correspond, respectively, to the part of the incident flux that is reflected at the effective potential barrier and to that which crosses the barrier and reemerges in the elastic channel after reflection at the most internal turning point.…”

Section: Investigation Of Refractive Effects In 12 C( 6 LI 6 Limentioning

confidence: 99%

Airy minima in the scattering of weakly bound light heavy ions

Michel

Ohkubo

2005

Phys. Rev. C

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We reanalyze the existing 6 Li + 12 C elastic scattering angular distributions for incident energies ranging from a few MeV to 318 MeV within the frame of the optical model. Despite the important breakup effects expected in the scattering of such a fragile projectile, the system is found to display a surprising transparency. Indeed the barrier-wave/internal-wave decomposition of the elastic scattering amplitude reveals that a substantial part of the incident flux that penetrates the nuclear interior reemerges in the elastic channel, and typical refractive effects, like Airy minima, are clearly identified in the angular distributions. Coupled channel calculations performed on 12 C( 6 Li, 6 Li') 12 C * (J π = 2 + , E x = 4.44 MeV) angular distributions extending through the whole angular range confirm the existence of an important internal-wave contribution in the backward hemisphere. A similar transparency is observed in other systems of this mass region, such as 7 Li + 12 C or 6 Li + 16 O. Finally, we examine recent 6 He + 12 C elastic scattering data obtained at 18 MeV by Milin et al. [Nucl. Phys. A730, 285 (2004)] and extending up to θ c.m. 85 • , and we suggest additional measurements that could ascertain whether some transparency persists in the scattering of this radioactive projectile.

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“…In the elastic channel, it is possible to circumvent the difficult semiclassical calculations (location of complex turning points, calculation of several action integrals in the complex plane) needed to isolate the barrier-wave and internalwave contributions to the scattering amplitude [15,16]; indeed it has been shown [26] that the relevant information can be obtained in a reliable way by performing several conventional OM calculations with modified versions of the original optical potential. For example, the BI decomposition can be carried out by analyzing the response of the elastic S matrix to perturbations of the potential in the internal region [26].…”

Section: Airy Structure In Elastic and Inelastic ␣ + 40 Ca Scattementioning

confidence: 99%

Airy structure in inelastic light-ion and light heavy-ion scattering

Michel

Ohkubo

2004

Phys. Rev. C

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We suggest that the transparency displayed by some light heavy-ion systems, such as 16 O+ 16 O, 16 O+ 12 C, or 12 C+ 12 C, which manifests itself by the emergence of Airy structure in the elastic scattering angular distributions and excitation functions, could also have observable consequences in some inelastic channels. Indeed benchmark calculations for the ␣ + 40 Ca light-ion system, where a similar mechanism dominates elastic scattering at low energy, reveals the persistence in inelastic scattering of the interference mechanism between the barrier-wave and internal-wave components of the scattering amplitude which underlies the Airy structure in the elastic channel. These calculations seem to point to new phase rules between the elastic and inelastic angular distributions.

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Quantum calculation of the barrier and internal wave contributions to light- and heavy-ion elastic scattering

Cited by 26 publications

References 16 publications

Coulomb amplitude representation and nuclear diffraction and refraction

Coulomb amplitude representation and nuclear diffraction and refraction

Airy minima in the scattering of weakly bound light heavy ions

Airy structure in inelastic light-ion and light heavy-ion scattering

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