Theoretical studies of , and clusters

Li ( H 2 O ) 19 - 21 + clusters with broken and distorted dodecahedral cages (metal in cavity) are studied by optimizing geometry at the B3LYP/6-311++G** level. The stabilization energy per monomer (SEP) for the Li ( H 2 O ) 19 + cluster (15.2 kcal/mol) is almost the same as that for the Li ( H 2 O ) 20 + cluster (15.1 kcal/mol) with a relatively large drop in the SEP value to 14.8 kcal/mol for the Li ( H 2 O ) 21 + cluster. While Li in Li ( H 2 O ) 20 + is negatively charged, it is neutral in Li ( H 2 O ) 19 + , and may favor the formation of Li ( H 2 O ) 20 + over Li ( H 2 O ) 19 + and hence, a magic peak in mass spectrum is expected at Li ( H 2 O ) 20 + .