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 (≲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.