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Rascher, R.; Müller, W. F. J.; Lieb, K. P.

doi:10.1103/physrevc.20.1028

Cited by 38 publications

(37 citation statements)

References 25 publications

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“…III) we believe this extrapolation to have been done properly. Furthermore, in a recent investigation of the 2VAI+ 160 system where fusion cross sections have been measured by the 7-ray technique [6] as well as the direct observation of evaporation residues [7] good agreement in the data was found. The 7-ray technique does not allow to distinguish between fusion-like and nonfusion-like (i.e.…”

mentioning

confidence: 62%

“…Instead of directly observing evaporation residues, which gets more difficult for lower bombarding energies, we chose to detect the secondary 7-ray transitions following particle evaporation. Although the direct population of residual groundstates cannot be measured, this 7-ray technique has been proven [6,7] to be a reliable means in the determination of o-fu s and hence be able to supplement data deduced through evaporation residue measurements.…”

Section: Introductionmentioning

confidence: 98%

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Complete fusion of7Li+16O in the region of the Coulomb threshold

Scholz

Ricken

Kuhlmann

1986

Z. Physik A - Atomic Nuclei

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Excitation functions of the one-and two-particle evaporation reactions 160(7Li, x~) and 160(7Li, xyT) , x, y=n, p, d, t and c~ have been measured in steps of 100-160 keV for ELi=4-10 MeV. All yield curves were rather smooth and could well be described by statistical model calculations taking into account one-and two-particle decays. No significant deviations of the total fusion cross section from the reaction cross section as given by the optical model were observed. A critical comparison is performed with earlier data of the same reaction taken at slightly higher energies where drastically reduced fusion cross sections were reported.

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mentioning

confidence: 62%

Section: Introductionmentioning

confidence: 98%

Complete fusion of7Li+16O in the region of the Coulomb threshold

Scholz

Ricken

Kuhlmann

1986

Z. Physik A - Atomic Nuclei

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“…O + 16 O, from[45] for16 O + 28 Si, and from[46] for28 Si + 28 Si. Digits next to lines with symbols indicate the values…”

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confidence: 99%

Quantitative analysis of precise heavy-ion fusion data at above-barrier energies using Skyrme-Hartree-Fock nuclear densities

2014

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We calculate the capture (fusion) cross sections for nine reactions involving spherical nuclei: 16 O + 16 O, 28 Si, 92 Zr, 144 Sm, 208 Pb; 28 Si + 28 Si, 92 Zr, 208 Pb; 32 S + 208 Pb. For six of them precision data are available in the literature. Analysis of these precision data within the framework of the single-barrier penetration model based on the Woods-Saxon profile for the strong nucleus-nucleus interaction potential (SnnP) gave rise to the problem of the apparently large diffuseness of the SnnP [Newton et al., Phys. Rev. C 70, 024605 (2004)]. Our fluctuation-dissipation trajectory model is based on the double-folding approach with the density-dependent M3Y NN forces including the finite-range exchange part. For the nuclear matter density the Skyrme-Hartree-Fock approach including the tensor interaction is applied. The resulting nucleus-nucleus potential possesses rather small (normal) diffuseness. The strength of the radial friction K R is used as the free parameter of the model. It turns out that for four of the five reactions induced by 16 O (except 16 O + 208 Pb) the calculated cross sections cannot be brought into agreement with the data within the experimental errors. This suggests that the calculated nuclear density is incorrect for 16 O. For the reactions not involving 16 O and, surprisingly, for the 16 O + 208 Pb reaction the agreement with the data within 2-5% is achieved at K R = 1.2 × 10 −2 to 3.0 × 10 −2 MeV −1 zs which is in accord with the previous works.

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“…The total reaction cross sections deduced from the resulting optical potentials are compared to the experimental fusion cross sections of ref. [18] in fig. 3.…”

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confidence: 99%

“…3. Data on the fusion cross section of 160 + 28Si from Rascher et al [18] are compared with the total reaction cross sections deduced from the resulting optical potentials.…”

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confidence: 99%

A phenomenological imaginary part of the optical potential for heavy ions

1983

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The depth of the imaginary part of the optical potential is derived from the assumption that, at a given energy and for each partial wave L, it is proportional to the compound nucleus density level up to a given excitation energy above the yrast level corresponding to the angular momentum L, and remains a constant for smaller values of L. The prescription is successfully tested for the system 160 + 28Si at nine different projectile energies between 33 and 81 MeV; it fails however at 141.5 MeV, as expected, because other channels, besides elastic scattering and fusion, are important.In heavy-ion physics the large decrease of the elastic cross section at energies where the nuclei begin to penetrate each other points to a large absorption out of the elastic channel. This is usually described by means of the imaginary potential in the optical model. During the last decade much effort has been made to derive this potential from different approaches [l-4] . In this paper, following a suggestion by Arima and Hodgson [5], we present a method to construct the imaginary part of the optical potential. This is inspired, in part, in the model proposed by Helling et al. [6] where that potential is given by the transition probability from the elastic channel into a precompound state which is a doorway state for the formation of the compound nucleus. This transition probability is given in first order by Fermi's golden rule:where p(E* , L) is the level density of the precompound nucleus with excitation energy E* and angular momentum L. ~iin+ is the interaction between the pre-_-. I compound state Gcomp and the elastic channel +elas. To estimate the magnitude of the transition matrix element it is necessary to introduce microscopic wave functions. Because the nucleons in the overlap region contribute most to the transition probability, Fink et al. [7] assume that the radial dependence of the square of the matrix element in (1) is proportional to 14 the number of nucleons in the overlap region. This suggests a factorization of the imaginary potential:where W(r) contains the radial dependence and W(E, L) the energy and angular momentum dependence through the level density p(E* , L) of the compound nucleus. This approximation implies that the formation of the compound nucleus is the dominant reaction mechanism. Such an assumption is reasonable only for not too high energy and not very heavy ions. This is one first limitation of our model. The yrast level is the state of highest possible angular momentum for a given excitation energy. Since angular rotations have usually the highest angular momentum, for a given energy the yrast level is reached if all excitation energy is converted into rotational energy. Bellow the yrast line of the compound nucleus the imaginary potential (2) is exactly zero since no compound states can be reached. Based on these ideas the imaginary part (2) of the optical potential may be expressed as follows: W(r) = { 1 + exp [(r -R)/a] }-l , R =Q,@;'~ +Ati3),

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Complete fusion ofO16,18with

Cited by 38 publications

References 25 publications

Complete fusion of7Li+16O in the region of the Coulomb threshold

Complete fusion of7Li+16O in the region of the Coulomb threshold

Quantitative analysis of precise heavy-ion fusion data at above-barrier energies using Skyrme-Hartree-Fock nuclear densities

A phenomenological imaginary part of the optical potential for heavy ions

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