Intrastate ?-transitions: A spectroscopic tool?

Abstract

In the framework of a potential model we have calculated the various bremsstrahlung cross sections into the SLi ground state, including M1 and E2 7-transitions leading from the high energy wing of the 5Li ground state resonance into states belonging to the same resonance at lower energy (intrastate transition). Our calculation supports the hypothesis of Schmalbrock et al. [1] that intrastate transitions of M 1 and E2 multipolarity exist. While we find a maximum cross section of roughly 1.4 nb for the E2 transition, we predict the cross sections for M1 intrastate transition to be less than 3.10 -5 nb. An experimental observation of the intrastate 7-ray emission appears to be very difficult due to the dominance of competing resonant (M 1) and direct (E 1) capture processes.Schmalbrock et al. have suggested to deduce magnetic dipole and electric quadrupole moments of resonant states from the measurements of the respective M 1 and E 2 intrastate transitions. We will show that the M1 intrastate cross sections do not yield the appropriate information to determine the magnetic dipole moment. We will also discuss that E2 intrastate transitions do not seem to be a suited tool to find the quadrupole moment of an unstable state.

Electromagnetic capture into theE x=7.56 MeV resonant state in15O

“…Applying penetrability ar-guments and considering the relative strength of the various multipole transitions in electromagnetic capture reactions we expect that the 7-radiation into the j~= 89 resonance is of E1 type being emitted by p + 14N p-waves with the total angular momentum j~ = 89 and .~_3-y -r , resp. Describing the fragments as structureless particles as this has been justified in studies of nuclear bremsstrahlung for the ~ + cr system [6] as well as the p+~ and p+~2C systems [7] we make the following ansatz for the p+ ~4N scattering states involved in the present capture process:…”