Attachment of very slow electrons to molecules and molecular clusters

Using a novel laser photoelectron attachment (LPA) method Klar et al. recently investigated free electron attachment processes with an effective resolution around 0.2 meV and demonstrated that the limiting E-1/2 dependence is only reached at very low energies (≤ 1 meV); moreover, they detected cusp-structure at onsets for vibrational excitation. In the present paper we describe efforts in this direction by applying the LPA method to studies of some molecular cluster systems. We performed experiments for the cluster targets SF6, CO2, N2O, O2 and a mixture of O2 with H2O and found three different types of behaviour for electron attachment near threshold. (author)