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1.
《Nuclear Physics A》1997,614(1):95-111
Angular distributions of 6Li+6Li elastic scattering were measured for Elab = 5–40 MeV. An optical model analysis of these data together with older data of 7Li+7Li elastic scattering taken at Elab = 8–17 MeV was performed with the aim to search for a “global” OM potential which describes elastic scattering in both LiLi systems in a broad energy range. Both surface and volume absorbing potentials can be found which fulfill this requirement if a linear energy dependence is assumed of the depths of the real as well as the imaginary potential. These depths, if fitted to individual angular distributions, are found to vary in a correlated manner with the beam energy. This is taken as indication of strong coupling between elastic, inelastic, and reaction channels. This is corroborated by the existence of resonances in reaction channels at these energies where the potential depths are most pronouncedly changing.  相似文献   

2.
Angular distributions of the 7Li + 10B elastic and inelastic scattering were measured at the energy E lab (10B) = 51 MeV (21 MeV c.m.). These and previously measured 7Li + 10B elastic-scattering data known at the 7Li-beam energies 24 MeV (14.1 MeV c.m.) and 39 MeV (22.94 MeV c.m.) were analyzed within the optical model and coupled-reaction channels method to determine the energy dependence of the parameters of the scattering potential and find the difference of these parameters from that of 7Li + 11B scattering. It was found that the 7Li + 11B potential parameters fail to describe the 7Li + 10B scattering data. The biggest difference is observed between the depths of the imaginary potentials that describe these scatterings.  相似文献   

3.
4.
The data for the 7Li + 9Be and 7Be + 9Be elastic scattering at the energies E lab(7Li) = 15.75 , 24, 30, 34, 63 and 130MeV and E lab(7Be) = 17 , 19 and 21MeV were analyzed within the optical model and coupled-reaction-channels method. The elastic and inelastic scattering, reorientation of 7Li , 7Be and 9Be as well as most important transfer reactions were included in the coupled-channels scheme. The resulting 7Li and 7Be potentials are very similar and have the same energy dependence. The real potential for recently derived 8Be + 9Be scattering potentials is very similar to that for 7Li , 7Be but the imaginary part of the 8Be one has a much greater strength at longer range.  相似文献   

5.
6.
A new measurement of differential cross sections for elastic p 6Li scattering in the energy range 0.35–1.2 MeV was performed. A partial-wave analysis of the data obtained in this way was carried out, and potentials simulating the p 6Li interaction were constructed. Various experiments devoted to studying elastic p 6Li scattering over the broad energy range of 0.5–50 MeV were analyzed on the basis of the optical model. By using the potentials obtained from the partial-wave analysis, the possibility of describing the astrophysical S factor for radiative proton capture on 6Li at low energies was considered within the potential cluster model involving forbidden states.  相似文献   

7.
8.
Differential cross sections for neutron elastic scattering in the energy range 7–26 MeV from 40Ca, 90Zr, 92Mo, 116, 124Sn and 208Pb are analyzed in terms of a global optical-model potential. A smooth variation of the real radius parameters with mass number is investigated. Otherwise, optical-model geometrical parameters are kept fixed at values obtained by averaging individual best fits. The energy and isospin dependences of potential strengths and volume integrals per nucleon are presented.  相似文献   

9.
《Nuclear Physics A》1997,617(3):265-281
Recent 11Li+p elastic scattering data at 62, 68.4, and 75 MeV and inelastic scattering data at 68.4 MeV, taken at RIKEN, are analysed with an isospin, density and momentum dependent finite range effective interaction (SBM) and M3Y interaction in a single folding model. The M3Y folded 11Li+p potentials are found to be almost similar to the folded 9Li+p potentials. But the SBM folded 11Li+p potentials are distinctly different, causing small but significant change in the angular distribution. Folded potentials need appreciable reduction factors indicating possible effects of strong breakup channel coupling. No significant change in results is found if 9Li core + Gaussian two-neutron halo density is used instead of the COSM density of 11Li although the radial extent of the latter is much larger. The angular distribution of the recently discovered excited state at 1.3 MeV, well reproduced by the SBM folded potential, is found to be predominantly dipole in nature.  相似文献   

10.
The possibility to construct intercluster interaction potentials in continuous and discrete spectra is shown in one‐channel cluster model based on the classification of orbital states according to Young schemes. These potentials usually contain Pauli forbidden states, and correctly describe elastic scattering phase shifts taking into account resonance behavior and main characteristics of the bound states of nuclei in the considering cluster channel. The versions of intercluster interaction potentials describing the resonance nature of some phase shifts of the n7Li elastic scattering at low energies and the P2 ground state of 8Li in the n7Li cluster channel have been constructed for the demonstration of this approach. The possibility of describing the total cross sections of 7Li (n,γ)8Li within the energies from 5 meV (5 · 10‐3 eV) to 1 MeV, including resonance at 0.25 MeV, has been demonstrated for the potentials obtained in the potential cluster model with forbidden states.  相似文献   

11.
Absolute differential cross sections for the elastic scattering of deuterons by7Li have been determined in the energy range of 1.0 to 2.6 MeV. Two excitation curves measured at laboratory angles of 90° and 160° vary smoothly with energy. At higher energies an extremely strong enhancement of the cross section relative to the Rutherford value was observed at large angles. It was, however, possible to find realistic optical potentials that describe these distributions fairly well over the whole energy region. For two of these potentials good fits could be obtained with DWBA calculations on the7Li (d, p 0)-reaction, one of them yielding a spectroscopic factor in close agreement with shell model predictions.  相似文献   

12.
13.
Existing experimental data on elastic and inelastic deuteron scattering on 6Li nuclei in the energy range from 8 to 50 MeV were analyzed within the approach of coupled reaction channels. The coupling of elastic scattering and inelastic scattering accompanied by the transition to the 3+ state at E x = 2.186 MeV and the mechanism involving the exchange of an alpha-particle cluster were taken into account in respective calculations. The phenomenological potentials obtained from the present analysis describe well experimental angular distributions at all energies and in full angular ranges. The depths of the real and imaginary parts of the potentials in question depend smoothly on energy at fixed values of the remaining parameters. The energy dependence of relevant volume integrals agrees well with similar data for the p + 6Li, ?? + 6Li, and 12C + 12C systems and with the predictions of a microscopic theory.  相似文献   

14.
The elastic scattering angular distributions for 7Li + 25Mg and 7Li + 27Al were measured at E(7Li) = 89 MeV over angular ranges of 8–55° c.m. and 8–64° c.m. Previously published measurements for 24, 26Mg at 89 MeV and 24Mg at 34 MeV are reanalyzed. The cross sections were analysed using a 6-parameter phenomenological Saxon-Woods potential. No discrete ambiguities were found but the usual continuous ambiguities exist. The data were also analysed with double folded real potentials generated using the M3Y effective interaction. The folded potential must be multiplied by about 0.6 to fit the data. The extent to which 7Li optical-model potentials are determined and suggestions for further work on the normalization of the folded potential are discussed.  相似文献   

15.
J. Cook 《Nuclear Physics A》1982,375(2):238-262
The energy dependence of 6Li optical potentials for elastic scattering from 28Si, 40Ca, 58Ni, 90Zr and 208Pb targets has been investigated by simultaneously fitting several data sets over a wide energy range. Both Saxon-Woods and double-folded real potentials have been used. In general, there is no requirement for energy dependence in either the real or imaginary potential for any of these targets, whether Saxon-Woods or folded real potentials are used. The main exception is 28Si when energy dependence is required to simultaneously fit low-energy data and high-energy rainbow scattering with folded potentials. The degree to which the potentials are determined is discussed.  相似文献   

16.
The optical potential for a composite particle is most simply approximated by the sum of the optical potentials of the constituent nucleons. Restricting ourselves to the real parts of the potentials we use this model as a first approximation in a calculation of the potentials for d, 3He, α and 12C. We add corrections for (i) the energy dependence of the nucleon potentials, (ii) three-body terms, (iii) the Pauli principle. All corrections can be important and that for the Pauli principle can be very large. We obtain a good explanation of the following phenomena: (a) the deuteron potential is nearly the sum of the neutron and proton potentials, (b) the potential for 3He is about 20 % less than the sum of the potentials of the nucleons in the 3He projectile, (c) the volume integral of the potential for 3He falls at both high and low energies in the energy range 20–100 MeV, (d) shallow potentials with large radii are found for low energy (30 MeV) scattering of α-particles, (e) deeper potentials are found for higher energy α-particle scattering. We predict shallow potentials for 12C scattering from light targets but deeper potentials for heavier targets.  相似文献   

17.
Detailed angular distributions for the elastic and inelastic scattering of 7Li at E = 36, 42, and 48 MeV and of 6Li at E = 38, 44, and 50 MeV by 54Fe have been measured. It is not possible to describe both sets of data with the same set of optical-model parameters. The ratio of UW is 0.8 for 7Li and 1.4 for 6Li at the strong absorption radius, implying stronger absorption for 7Li than for 6Li. No energy dependence in the optical-model parameters was necessary for either 6Li or 7Li. The inelastic scattering from the 54Fe 2+, 1.41 MeV state was well described by the DWBA and the extracted deformation length (βR = 0.62) was the same for both 6Li and 7Li scattering. It was not possible to describe the 7Li projectile excitation data with collective-model DWBA calculations showing that more detailed calculations for the projectile excitation are necessary.  相似文献   

18.
Previously measured angular distributions of the differential cross section and the tensor analyzing powerT 20 for the scattering of7Li from51V in the energy range from 10 to 18 MeV were analyzed with the double folding model using the effective nucleon-nucleon interaction M3Y as well as a zero range effective nucleon-nucleon interaction. Due to the spectroscopic deformation of the7Li-nucleus the interaction potential contains a central and aT R -tensor part. The latter one is the origin of the observed tensor analyzing powers. Within the same model the scattering of aligned7Li-nuclei from58Ni at 14.2 and 20.3 MeV is well described. The strength of theT R -tensor potential in relation to the spectroscopic mass deformation of7Li is discussed. Using the real interaction potential obtained by the double folding model the energy dependence of the total reaction cross sectionσ r and its tensor analyzing powerT 20 r for the system7Li?51V is well described within a barrier penetration model.  相似文献   

19.
Differential cross sections and vector analyzing powers are calculated for the elastic scattering of protons by lithium isotopes 6Li, 7Li, 8Li, and 9Li at energies of 60 and 200 MeV. The calculations are performed using Glauber??s multiple diffraction scattering theory in the two-particle (for 7Li) and three-particle (for 6,8,9Li) models with realistic intercluster interaction potentials. An analysis of the relationship between the differential elastic scattering cross section and various wave functions, calculated using different interaction potentials, is presented for the 8, 9Li isotopes.  相似文献   

20.
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