Ab Initio study on the superatomic nature of Li 2 H 3 +/− and their mutual interaction

The clusters that imitate atoms from the periodic table are known as superatoms. Superalkalis and superhalogens are two subsets of superatoms imitating the alkali and halogen atoms, respectively. Considering the dual position of hydrogen in the periodic table, we study the ionic Li 2 H 3 complexes using the MP2/6-311++G(d,p) level of theory and notice that its cation and anion may behave as superalkali and superhalogen, respectively. Further, their interaction leads to the (Li 2 H 3 ) 2 dimer, whose possible dissociation pathways have been thoroughly analysed. Although this dimer is found to be stable against dissociation to both neutral and ionic fragments, it can undergo dehydrogenation, providing a (LiH) 4 cluster and an H 2 molecule. Moreover, the rehydrogenation of the (LiH) 2 or (LiH) 3 cluster further results in this dimer, suggesting its possible role in the dehydrogenation-rehydrogenation. These findings may provide some theoretical insights for future researchers working on the hydrogenation of lithium and related species.