[en] The ¹⁹F(⁷Li,⁷Be)¹⁹O charge-exchange reaction at 52.2MeV incident energy has been studied at the INFN-LNS laboratory in Catania (Italy) using the MAGNEX spectrometer. Thanks to an algebraic ray-reconstruction technique and to a high-performing focal plane detector, high-resolution ¹⁹O energy spectra and angular distributions have been extracted. A theoretical analysis of the reaction in the framework of the Charge-Exchange Quasiparticle Random Phase Approximation (CEX-QRPA) has been done. The results of Distorted-Wave Born Approxiation (DWBA) calculations in a double folding scheme have been compared to the experimental angular distribution of the transition to the 19O state at 1.47MeV state and show a remarkable agreement both in magnitude and shape.

[en] Charge-changing collisions of heavy ions at high energies are discussed with respect to the design of a high energy accelerator. In the first part different methods for the estimation of average charge states are compared. The formulae of Nikolaev and of Betz et al. result in quite different values for the energies at which fully stripped ions might be obtained when coefficients in both formulae are adjusted to reflect the average charge states observed experimentally at lower energies. On the other hand N. Bohr's criterium seems to give useful results without any adjustment of parameters. According to this criterium one would expect at least 10% fully stripped uranium ions at an energy of 235 MeV/amu. (orig.)

[en] The Rb charge exchange cell is constructed as the He^- ion source of the SNU 1.5-MV Tandem Van de Graaff accelerator. the characteristic experiments is carried out in order to determine the optimum operational conditions of the cell. The He⁺ ion beam with the energy of 1 - 10 keV, extracted from the duoplasmatron ion source, is passed through the Rb vapor to become He^-ions by the two step charge exchange reaction, i.e., He⁺ + Rb → He^o* + Rb⁺ and He^o* + Rb → He^- + Rb⁺. From the experimental results, it is found that the maximum fractional yield of He^- ions is produced at He⁺/ion energy of 7 keV. The optimum temperatures of the oven and the canal are determined to be 370 deg C and 95 deg C respectively. Under the optimum operational condition the maximum fractional yield of He^- ions is 2.42 ± 0.02 5. This charge exchange cell is proved to be an effective system for the production of He^- ions. (Author)

[en] There is a recently renewed interest on the study of single and double charge exchange reactions with heavy ions. We report here a preliminary theoretical study of double charge exchange reactions in terms of two successive charge exchanges in 2^nd order Distorted Wave Born approximation. This allows us to include the effect of the different transfer channels in an approximate way. Evidences show that the charge exchange process is dominant. The following one in importance is the combination of one single charge exchange, one neutron pick-up and one proton stripping. This particular process calls for further investigation. (paper)

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[en] The available data on the forward charge exchange of nucleons on the deuteron up to 2 GeV/nucleon are reviewed. The value of the inclusive nd → pnn / np → pn cross section ratio is sensitive to the fraction of spin-independent neutron-proton backward scattering. The measurements of the polarisation transfer in d (n, p ){ nn } or the deuteron analysing power in p { d, { pp }) n in high-resolution experiments, where the final nn or pp pair emerge at low excitation energy, depend upon the longitudinal and transverse spin-spin up amplitudes. The relation between these types of experiments is discussed and the results compared with predictions of the impulse approximation model in order to see what new constraints they can bring to the neutron-proton database.

[en] The formation of charge-transfer complexes as derivatization reactions for fast-atom-bombardment (f.a.b.) mass spectrometry has been investigated. The donor N,N,N',N'-tetramethyl-1,4-phenylenediamine (TMPD) and the acceptor 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ) were studied. Results suggest that although a strong charge-transfer complex is formed, protonation of the donor molecule occurs whenever possible. Characteristic ultraviolet/visible spectra of charge-transfer complexes clarify the competing processes of electron and proton transfer, and their time dependence. Charge-transfer derivatization is used to increase signals for the donor cation radicals of anthracene/picric acid, pyrene/picric acid, and indole/trinitrofluorenone. (Auth.)

[en] In double charge exchange leading to residual nonanalog 0⁺ ground states, we examine the relative contribution of sequential charge exchange and delta-nucleon charge exchange. We conclude that the data cannot be quantitatively understood in terms of these two reaction mechanisms

No abstract available