共查询到20条相似文献,搜索用时 15 毫秒
1.
S. Kamerdzhiev J. Speth G. Tertychny 《The European Physical Journal A - Hadrons and Nuclei》2000,7(4):483-490
Recent experimental studies of the giant electric resonance region in 58Ni and 40Ca with inelastically scattered α-particles of energy Eα= 240 MeV are analyzed within a microscopic nuclear structure model.
The model includes the continuum RPA and more complex 1p1h⊗phonon configurations. By superimposing the contributions of different
multipoles up to L = 4 we obtain good agreement with the newest (reanalyzed) data for the isoscalar monopole strength and
for the total (α,α′) cross section in 58Ni. Agreement with experiment for the isoscalar monopole resonance in 40Ca is obtained too. We emphasize the necessity of using microscopic transition densities and discuss consequences for the
analyses of such experiments in light and medium mass nuclei. It is shown that the gross structure of the isoscalar monopole
resonance in 40Ca is caused by the 1p1h⊗phonon configurations.
Received: 23 December 1999 / Revised version: 28 February 2000 相似文献
2.
L. Vannucci U. Abbondanno M. Bettiolo M. Bruno N. Cindro M. D’Agostino P. M. Milazzo R. A. Ricci T. Ritz W. Scheid G. Vannini 《Zeitschrift für Physik A Hadrons and Nuclei》1996,355(1):41-54
Excitation functions and angular distributions of58Ni+58Ni and58Ni+62Ni scattering at energies just above the Coulomb barrier have been measured aroundθ cm=90° in energy stepsΔE cm=0.25 MeV fromE cm ? 110 MeV toE cm ? 120 MeV for58Ni+58Ni and fromE cm ? 110 MeV toE cm ? 118 MeV for58Ni+62Ni. Evidence for structure of non-statistical character has been found in the angle-summed excitation functions; this evidence is corroborated by the analysis of the angular distributions. This is the first time that non-statistical structure in elastic and inelastic scattering is reported with high confidence level for this mass and excitation energy ranges. Attempts are presented to understand the nature of this structure, including the presence of intermediate dinuclear states and virtual states in a potential well. 相似文献
3.
S. Yu. Kun U. Abbondanno M. Bruno N. Cindro M. D’Agostino P. M. Milazzo R. A. Ricci T. Ritz B. A. Robson W. Scheid A. V. Vagov G. Vannini L. Vannucci 《Zeitschrift für Physik A Hadrons and Nuclei》1997,359(2):145-148
Structures of non-statistical character, recently observed in 58 Ni +46 Ti elastic and 58 Ni +62 Ni elastic and inelastic excitation functions, produce damped oscillations in the cross section energy autocorrelation functions. The analysis of these damped oscillations in terms of S-matrix spin and parity decoherence indicates, as a possible interpretation, damping of the coherent rotational motion of the intermediate dinuclear system formed in the reaction. 相似文献
4.
The zero-field level crossing effect in selective reflection from an atomic vapour is calculated for normally incident radiation using a theory which, unlike the conventional dispersion theory, includes the effect of transient polarization behaviour due to diffuse wall collisions of vapour atoms. Both longitudinal and transverse magnetic fields are considered. At low vapour densities we find a narrowing of the level crossing curve in selective reflection relative to its width in the conventional dispersion theory. The narrowing is calculated as a function of the ratio of the homogeneous and inhomogeneous line width of the vapour for a Maxwellian velocity distribution of the vapour atoms and spectrally uniform incident radiation. The theory of this paper offers an explanation for recent observations of narrowing of level crossing curves in selective reflection. 相似文献
5.
A generalized semiclassical treatment for the elastic scattering of heavy ions is developed in the presence of a complex optical potential. The scattering phase shift and its derivatives with respect to the impact parameter are calculated after extending the JWKBL approximation. The results are compared with experimental data for the elastic scattering of16O from medium and heavy target nuclei and relation between the present treatment and that of the optical model and Regge pole analysis is established 相似文献
6.
T. Feldker L. Pelzer M. Stappel P. Bachor R. Steinborn D. Kolbe J. Walz F. Schmidt-Kaler 《Applied physics. B, Lasers and optics》2014,114(1-2):11-16
We present studies of mixed Coulomb crystals of 40Ca+ and 40Ca2+ ions in a linear Paul trap. Doubly charged ions are produced by photoionization of trapped 40Ca+ with a vacuum ultraviolet laser source and sympathetically cooled via Doppler cooled 40Ca+ ions. We investigate experimentally and theoretically the structural configurations and the vibrational modes of these mixed crystals. Our results with 40Ca2+ are an important step towards experimental realization of the proposals for mode shaping in a linear crystal and spin-dependent configuration changes from zigzag to linear as proposed by Li et al. (Phys Rev A 87:052304, 2013) and Li and Lesanovsky (Phys Rev Lett 108:023003, 2012) using ions excited to Rydberg states. 相似文献
7.
R. Da Silveira 《Physics letters. [Part B]》1973,45(3):211-213
It is shown that the oscillatory behaviour of differential cross section of heavy ion elastic scattering, which satisfies the semi classical conditions, is well described in terms of interference effects due to a rainbow. 相似文献
8.
J. Galin B. Gatty D. Guerreau M. Lefort X. Tarrago R. Babinet B. Cauvin J. Girard H. Nifenecker 《Zeitschrift für Physik A Hadrons and Nuclei》1976,278(4):347-352
A careful exploration of the angular distribution for the products emitted mainly below the grazing angle shows the continuous evolution from Q.E. to completely damped collisions. The relative relaxation time of the collective degrees of freedom is considered. 相似文献
9.
The contributions of two-particle transfer to elastic and inelastic scattering of heavy ions are treated simultaneously in the coupled channels framework using microscopic transfer form factors. As an example, the reaction 18O(16O, 16O)18O(g.s. and 21+) is investigated at three energies near the Coulomb barrier. The interference between scattering and transfer leads to a consistent interpretation of both elastic and inelastic data. Indirect transfer contributions give relatively small, but non-negligible corrections to the direct scattering plus transfer result, removing a previously reported energy dependence of the spectroscopic factor. 相似文献
10.
A. N. Antonov Chr V. Christov I. Zh. Petkov 《Zeitschrift für Physik A Hadrons and Nuclei》1985,320(4):683-687
The 1.04 GeV-proton elastic scattering from40Ca is studied in the framework of the coherent density fluctuation model (CDFM). The calculations are carried out in the Glauber theoretical scheme with three different charge densities. It is shown that:i) the account of the flucton correlations leads to results considerably different from those obtained in the independent particle Glauber approach (IPGA);ii) in contrast to the case of IPGA the use of a more realistic density improves the agreement of CDFM-results with the experimental data. 相似文献
11.
Torsten Fliessbach 《Zeitschrift für Physik A Hadrons and Nuclei》1971,247(2):117-126
For the elastic scattering of heavy ions a microscopic model is developed which uses shell model wave functions which are localised at a certain distance both in coordinate and momentum space. The antisymmetrization is treated exactly. Using oscillator functions and the Brink-Boeker force the energy dependent real part of the optical potential for O16- O16 scattering is numerically determined. The results are compared with the analysis of experiments. 相似文献
12.
H. Wojciechowski D.E. Gustafson L.R. Medsker R.H. Davis 《Physics letters. [Part B]》1976,63(4):413-415
A model-independent method of obtaining total reaction cross sections has been applied to α-particle and 16O, 40Ar and 84Kr elastic scattering. Results are compared with total reaction cross sections determined by other means. 相似文献
13.
Relativistic corrections to the reaction kinematic parameters were made for elastic scattering of 6Li, 12C and 40Ar from 40Ca, 90Zr and 208Pb targets at incident energies between 20 and 100 MeV/nucleon. The results of optical model calculations show that the effects of such corrections are important when describing the angular distributions of elastic scattering cross sections for heavy ion scattering at incident energies as low as around 40 MeV/nucleon. The effects on the total reaction cross sections on the other hand, were found to be small within the energy range studied when the optical model potential is fixed. 相似文献
14.
《Nuclear Physics A》1987,462(3):413-444
Differential cross sections for the elastic scattering of neutrons from 40Ca have been measured in the 19–26 MeV region. The neutron elastic scattering data, previous neutron measurements and additional proton elastic scattering data are analyzed using three different approaches to the optical model potential: Woods-Saxon parameterization, model independent analysis and microscopic calculations. The difference between the phenomenological neutron and proton real potentials is studied in terms of Coulomb effects, nuclear polarization and charge symmetry breaking in the nuclear mean field. 相似文献
15.
K.M. Hartmann 《Nuclear Physics A》1976,269(1):237-251
The elastic scattering amplitude is divided into contributions arising from the “near” and “far” sides of the interaction region. Each of these contributions is further divided into a diffractive component arising from strong absorption and refractive components arising from the repulsive Coulomb and attractive nuclear fields. Damped orbiting of the projectile around the target is also allowed for. Simple closed form expressions are derived for the various contributions by assuming specific forms for the elastic scattering matrix. The results are discussed by analysing several typical elastic scattering data. 相似文献
16.
17.
W. Dreves P. Zupranski P. Egelhof D. Kassen E. Steffens W. Weiss D. Fick 《Physics letters. [Part B]》1978,78(1):36-40
The elastic scattering of aligned 6Li and 7Li on 58Ni at Ecm = 12.7 MeV displays an “isotopic” effect which can be traced to the very different (mass) quadrupole moments of both isotopes. The elastic scattering of aligned 6Li and 7Li on 12,13C at ELi = 9 MeV displays large effects, but the angular dependence is much more complicated compared to the scattering on 58Ni. 相似文献
18.
Carter J. Feldmeier H. Richter A. Schrieder G. Wastyn P. 《Zeitschrift für Physik A Hadrons and Nuclei》1981,301(4):365-366
Using a strongly mismatched transfer reaction,138Ba (14C,15N), the spin orbit potential for15N projectiles has been derived in terms of the reaction asymmetry. The strength and sign of the L·S-potential are consistent with a previous determination using an (16O,15n) reaction; the signis opposite to that for nucleons and agrees with a model where the last P1/2 nucleon is responsible for the L·S potential. 相似文献
19.
K. Mikhailov A. Stavinskiy J. C. Angelique B. Benoit E. de Goes Brennand G. Bizard J. Colin G. Costa P. Désesquelles O. Dorvaux D. Durand B. Erazmus Yu. Grishuk F. Hanappe A. Kieliszek S. Kuleshov C. Lebrun R. Lednicky G. Leksin P. Leszczynski M. Marques Th. Materna K. Miller G. Papatheofanous T. Pawlak J. Pluta M. Przewlocki A. Staranowicz L. Stuttge B. Tamain A. Vlasov L. Vorobyev K. Wosinska 《The European Physical Journal A - Hadrons and Nuclei》2003,18(4):645-651
Results of the experimental study of p
4
He, d
3
He, dT, pT, p
3
He and, for the first time, nT, n
3
He, n
4
He correlations in the region of small relative momenta are presented. The data analysis provides an estimate of the effective source size or emission time.Received: 26 May 2003, Published online: 2 December 2003PACS:
25.70.Pq Multifragment emission and correlations 相似文献
20.
Rehm KE Jiang CL Ahmad I Caggiano J Collon P Greene JP Henderson D Heinz A Janssens RV Pardo RC Pennington T Schiffer JP Siemssen RH Wuosmaa AH Paul M Mohr P 《Physical review letters》2002,89(13):132501
Scattering of alpha particles from 44Ti, the lightest unstable alpha-particle nucleus above A=40, has been measured at backward angles. The "anomalous" order-of-magnitude enhancement that is characteristic of 40Ca and other light alpha-particle nuclei is not observed. Instead, the backward yield is similar to that observed for other nuclei heavier than 40Ca, and is well described with average optical model parameters. 相似文献