Theoretical Studies on the Potential Energy Surfaces of N8 Clusters

The potential energy surfaces for the synthesis and decomposition reaction of N 8 ( C S ) → N 5 + + N 3 - and isomerization reaction of N 8 ( C S ) to N 8 ( C 2 h ) were investigated by density functional theory (DFT). The species involved were fully optimized using four DFT methods. Relative energies were further calculated at the QCISD/6-311+G*//B3LYP/6-311+G* level. The barrier heights of N 8 ( C S ) → N 5 + + N 3 - in forward and reverse directions were predicted to be 23.4 and 2.0 kcal/mol, respectively. Rate constants for the dissociation and synthesis pathways of N 8 ( C S ) were found by use of variational transition state theory. The barrier height for the isomerization reaction of N 8 ( C S ) to N 8 ( C 2 h ) was predicted to be 4.0 kcal/mol at the QCISD/6-311+G*//B3LYP/6-311+G* level.