POSITRONIC IONS OF METALLIC CLUSTERS

We demonstrate the possibility of a new class of positronic ions, form ed by attaching a positron to the induced dipole of a metallic cluster . It is shown that such a system is made stable by the inclusion of th e polarization potential. Ground state and some excited state energies are given, both for the positronic and for the corresponding electron ic ion of Nas and Nato clusters. We also give total cross sections for capture in both cases as a function of projectile energy up to 3 eV, and compare the results for both species of ions.