Search results for "Coulomb"
showing 10 items of 379 documents
Isospin symmetry in thesdshell: Transition strengths in the neutron-deficientsdshell nucleusAr33
2014
Reduced transition strengths of the deexciting transitions from the first two excited states in 33Ar were measured in a relativistic Coulomb excitation experiment at the GSI Helmholtz center. The radioactive ion beam was produced by fragmentation of a primary 36Ar beam on a 9Be target followed by the selection of the reaction product of interest via the GSI Fragment Separator. The 33Ar beam hit a secondary 197Au target with an energy of approximately 145 MeV/nucleon. An array of high-purity germanium cluster detectors and large-volume BaF2 scintillator detectors were employed for γ -ray spectroscopy at the secondary target position. The Lund-York-Cologne Calorimeter was used to track the ou…
Excitation functions for production of heavy actinides from interactions ofCa40andCa48ions withCm248
1985
Excitation functions have been measured for production of isotopes of Bk through Fm in bombardments of /sup 248/Cm with 234- to 294-MeV /sup 40/Ca ions and with 239- to 318-MeV /sup 48/Ca ions. The maxima of the isotopic distributions for these elements occur at only 2 to 3 mass numbers larger for /sup 48/Ca than for /sup 40/Ca reactions. The shapes of the distributions and the half-widths of about 2.5 mass numbers are quite similar to those observed previously for reactions of /sup 16/O, /sup 18/O, /sup 20/Ne, and /sup 22/Ne with /sup 248/Cm. In general, the excitation functions for /sup 40/Ca show maxima near the Coulomb barrier while those for /sup 48/Ca are about 20 MeV above the barrie…
Shape dynamics in neutron-rich Kr isotopes: Coulomb excitation of 92Kr, 94Kr and 96Kr
2013
We report on the study of excited states in 92,94,96Kr populated via projectile Coulomb excitation at safe energies. The radioactive ion beams at energies of 2.85 MeV/u were delivered by the REX-ISOLDE facility at CERN and impinged on self-supporting 194,196Pt targets. The emitted γ -rays were detected by the Miniball detector-array. A detailed description of the experimental techniques used for extracting diagonal and transitional matrix elements and of the theoretical framework is given. The present experiment reveals the moderate evolution of the collective structure in the considered neutron-rich Kr isotopic chain, which is supported by the interacting boson model combined with the self…
Inclusive quasielastic charged-current neutrino-nucleus reactions
2004
The Quasi-Elastic (QE) contribution of the nuclear inclusive electron scattering model developed in Nucl. Phys. A627 (1997) 543 is extended to the study of electroweak Charged Current (CC) induced nuclear reactions, at intermediate energies of interest for future neutrino oscillation experiments. The model accounts for, among other nuclear effects, long range nuclear (RPA) correlations, Final State Interaction (FSI) and Coulomb corrections. Predictions for the inclusive muon capture in $^{12}$C and the reaction $^{12}$C $(\nu_\mu,\mu^-)X$ near threshold are also given. RPA correlations are shown to play a crucial role and their inclusion leads to one of the best existing simultaneous descri…
Inclusive quasielastic neutrino reactions inC12andO16at intermediate energies
1993
Inclusive quasielastic neutrino (antineutrino) reactions on [sup 12]C and [sup 16]O at intermediate energies (50[lt][ital E][lt]400 MeV) are studied to investigate the effects of the nuclear medium on the total cross section and the energy spectrum of the outgoing leptons. The calculations are done in the local density approximation and various nuclear effects like Pauli blocking, Fermi motion, and strong-interaction renormalizations due to the presence of nucleons are taken into account. The corrections due to Coulomb effects are included which have been hitherto neglected in inclusive reactions. The results presented here are applicable to the inclusive reactions with neutrino beams plann…
Coulomb effects in deuteron breakup by proton impact
1994
We present the first results of a calculation of kinematically complete differential cross sections for the proton-induced deuteron breakup reaction, obtained by using a three-body formalism based on momentum space integral equations which correctly takes into account the Coulomb repulsion between the two protons. Comparison with experimental data is made.
Statistical characterization of self-assembled charged nanoparticle structures
2013
We propose a novel approach for description of dynamics of nanostructure formation for a system consisting of oppositely charged particles. The combination of numerical solution of analytical Bogolyubov–Born–Green–Kirkwood–Yvon (BBGKY) type equation set with reverse Monte Carlo (RMC) method allows us to overcome difficulties of standard approaches, such as kinetic Monte Carlo or Molecular Dynamics, to describe effects of long-range Coulomb interactions. Moreover, this allows one to study the system dynamics on realistic time and length scales. We applied this method to a simple short-range Lenard–Jones (LJ)-like three- (3D) and two-dimensional (2D) system combining the long-range Coulomb an…
Production of dianionic and trianionic noble metal clusters in a Penning trap
2003
Abstract Metal clusters, Aun−, Agn−, and Cun−, from a laser vaporization source are transferred to a Penning trap and subjected to a bath of simultaneously stored electrons. After some reaction period multiply charged anionic gold, silver, and copper clusters are observed if the clusters under investigation are large enough. The cluster sizes for the onset of the formation of dianions and trianions are compared to a charged sphere model. The description of the experimental findings is largely improved if the repulsive Coulomb barrier is taken into account which prevents autodetachment of the surplus electrons on the experimental time scale of a second.
Analytic evaluation of first-order properties within the mean-field variant of spin-free exact two-component theory.
2019
We present a scheme for the calculation of energies and analytic energy gradients within spin-free exact two-component (SFX2C) theory in its mean-field variant, which we refer to as SFX2C-mf. In the presented scheme, the Foldy-Wouthuysen transformation is carried out after the spin-free four-component Hartree-Fock treatment such that in electron-correlated calculations only the non-mean-field part of the two-electron interactions is handled in an untransformed manner. The formulation of analytic gradients requires some adjustments in comparison with the nonrelativistic case, i.e., the additional solution of the spin-free Dirac Coulomb coupled-perturbed Hartee-Fock equations together with a …
Cost-Effective Treatment of Scalar Relativistic Effects for Multireference Systems: A CASSCF Implementation Based on the Spin-free Dirac-Coulomb Hami…
2016
We present an implementation of the complete active space-self-consistent field (CASSCF) method specifically designed to be used in four-component scalar relativistic calculations based on the spin-free Dirac-Coulomb (SFDC) Hamiltonian. Our implementation takes full advantage of the properties of the SFDC Hamiltonian that allow us to use real algebra and to exploit point-group and spin symmetry to their full extent while including in a rigorous way scalar relativistic effects in the treatment. The SFDC-CASSCF treatment is more expensive than its non-relativistic counterpart only in the orbital optimization step, while exhibiting the same computational cost for the rate-determining full conf…