Negative ion formation in lithium atom collisions

The formation of Li- by dissociative attachment in e+Li2 collisions is characterized by a large cross section for electron attachment to highly vibrationally excited Li2 molecules. However, the electronic structure of the Li-2 system dictates that low energy electrons (approx. <0.2 eV) are needed to minimize loss processes. An alternate production route for Li- is possible via direct ion-pair formation through collisions of highly excited (Rydberg) Li atoms. The mechanisms for ion-pair formation will be discussed in terms of the high-lying molecular Rydberg states of Li2