arXiv subjects

R. Schmidt

Publications and source records attributed to R. Schmidt.

75 records · Page 5Linked to original sources

arXiv1997

Charge Transfer in Cluster-Atom Collisions Studied with Non-Adiabatic Quantum Molecular Dynamics

Charge transfer in collisions of Na_n^+ cluster ions with Cs atoms is investigated theoretically in the microscopic framework of non-adiabatic quantum molecular dynamics. The competing reaction channels and related processes affecting the charge transfer (electronic excitations, fragmentation, temperature) are described. Absolute charge transfer cross sections for Na_n^+(2.7 keV) + Cs --> Na_n + Cs^+ have been calculated in the size range 4 <= n <= 11 reproducing the size dependence of the experimental cross sections. The energy dependence of the cross section is predicted for n=4,7,9. An exotic charge transfer channel producing Cs^- is found to have a finite probability.

physics.atm-clus↗

arXiv1997

On the Gerasimov-Drell-Hearn sum rule for the deuteron

The Gerasimov-Drell-Hearn sum rule is evaluated for the deuteron by explicit integration up to a photon energy of 550 MeV including contributions from the photodisintegration channel and from coherent and incoherent single pion production as well. The photodisintegration channel converges fast enough in this energy range and gives a large negative contribution, essentially from the $^1S_0$ resonant state near threshold. Its absolute value is about the same size than the sum of proton and neutron GDH values. It is only partially cancelled by the single pion production contribution. But the incoherent channel has not reached convergence at 550 MeV.

nucl-th↗

arXiv1996

Quasifree pion photoproduction on the deuteron in the $Δ$ region

Photo production of pions on the deuteron is studied in the spectator nucleon model. The Born terms of the elementary production amplitude are determined in pseudovector $π$N coupling and supplied with a form factor. The $Δ$ resonance is considered both in the $s$ and the $u$ channel. The parameters of the $Δ$ resonance and the cutoff of the form factors are fixed on the leading photoproduction multipoles. Results for total and differential cross sections are compared with experimental data. Particular attention is paid to the role of Pauli correlations of the final state nucleons in the quasifree case. The results are compared with those for pion photoproduction on the nucleon.

nucl-th↗