Multiple electromagnetic excitation in fast peripheral heavy ions collisions

Abstract

We study the corrections of first order electromagnetic excitation due to higher order electromagnetic interactions. An effective operator is introduced which takes these effects into account in the sudden approximation.Evaluating the matrix-elements of this operator between the relevant states corrections to the first order result are obtained in a simple way. As an example we discuss the excitation of the first excited state in 11 Be. It tends to improve the agreement between experiment and theory.

Scaling laws and higher-order effects in Coulomb excitation of neutron halo nuclei

“…We find r(z) ≈ 1 − 0.619 z 2 in lowest order in z. It seems of interest to compare the results of [5] with the present one. In [5] two different models (denoted by I and II) were used.…”

“…It seems of interest to compare the results of [5] with the present one. In [5] two different models (denoted by I and II) were used. Expanding in the strength parameter z we get r I (z) = 1 − 6z 2 /5 + .…”

“…It is also neglected in our model space. [5] that third-order E1 excitation is more important than second-order E1-E2 excitation. The role of higher multipole excitations in the electromagnetic excitation of one-neutron halo nuclei is also studied in [18].…”

“…This is reasonably well fulfilled for 11 Be, even at GANIL energies. In [5] higher-order effects in the electromagnetic excitation of 11 Be to the 1/2 − bound state were studied using the sudden approximation. In [6] a continuum discretized coupled channels approach was adopted.…”

“…We deal here with the second question: higher-order electromagnetic excitation. This problem was studied for the 11 Be case in the mid-nineties by two groups [5,6]. In view of recent advances in the description of the electromagnetic properties of halo nuclei, see e.g.…”