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The photoionization process of the C5+ ion in warm, dense plasmas is studied using the relativistic approximation. Cross section calculations are performed for plasma density and temperature ranges of ne ∼ 1023–1026 cm−3 and Te = 150–300 eV, respectively. The used static screened potential includes the effects of plasma degeneracy, finite-temperature gradient corrections to the kinetic energy, and quantum exchange-correlation. The dependencies of the photoionization cross section on plasma density (for fixed temperature) and temperature (for fixed density) are investigated. [ABSTRACT FROM AUTHOR]

The two-center atomic orbital close-coupling method is employed to study electron capture and excitation reactions in collisions of Liq+ (q=1-3) ions with ground state atomic hydrogen in the ion energy range from 0.1 keV/u to 300 keV/u, where u is the atomic mass unit. The interaction of the active electron with the projectile ions (Li+, Li2+) is represented by a model potential. Total and state-selective cross sections for charge transfer and excitation processes are calculated and compared with data from other sources when available. [ABSTRACT FROM AUTHOR]

The electron capture and excitation processes in collisions of H⁺ with excited He.(1s2s; ¹,³S) atoms are investigated theoretically by using the two-centre atomic orbital close-coupling method in the energy range 2.200 keV u-1. The interaction of active electrons with the target ion is represented by a model potential different for the singlet and triplet systems of He states. In the electron capture studies, the basis included all the He (1s, n ≤ 6) discrete states and all the H (n ≤ 7) states plus 202 pseudostates, while for the excitation studies all the He (1s, n ≤ 8) states plus 244 pseudostates and all the H (n ≤ 5) discrete states were included in the basis. The excitation cross section results of the present calculations are compared with other theoretical results and good agreement is obtained at high collision energies. For energies below 6 keV u-1, the present excitation and electron capture results are compared with those from the recent quantal molecular orbital close-coupling calculations showing good agreement for the dominant channels. It is found that the cross sections for excitation and state-selective electron capture are significantly different for the singlet and triplet states, particularly in the low-energy region. [ABSTRACT FROM AUTHOR]

We report the results of the measurements of complete and incomplete fusion of the 9Be + 169Tm and 187Re systems at energies close to the Coulomb barrier. The activation technique with the detection of offline gamma rays was used to derive the cross sections. By comparing the experimental cross sections with coupled-channel calculations that do not include the breakup channel, we found suppression of the complete fusion of the order of 30% for both systems, at energies slightly above the barrier. This suppression corresponds roughly to the measured incomplete fusion. We also investigate a systematic behavior of the suppression of complete fusion cross sections for 9Be on different targets and we found that it does not depend on the target. [ABSTRACT FROM AUTHOR]

Complete and incomplete fusion cross sections for the 9Be + 181Ta system were measured at near barrier energies, using the offline gamma ray spectroscopy method. The results were compared with coupled channel calculations that do not take into account the coupling of the breakup channel, using a double folding potential as bare potential. A complete fusion suppression of the order of 35% was found, at energies above the barrier, whereas the total fusion cross sections are in agreement with the calculations. The ratio between incomplete fusion and total fusion at energies above the Coulomb barrier was found to be 32 ± 1%. At sub-bamer energies one observes some enhancement of total fusion cross section. [ABSTRACT FROM AUTHOR]