Theoretical study of the substituent effects on structure and dissociation of RNSi and RSiN (R = H, Li)

The effects of substituent on stability, structural properties and dissociation of HSiN, LiSiN and their isomers have been studied in detail using ab initio MP2, CCSD and CCSD(T) and density functional B3LYP methods. After dissociation of HNSi, LiNSi, HSiN and LiSiN, the fragmented atoms have been considered to be either in their ground state or in their valence excited state in various dissociation channels. Only allowed dissociations of these molecules are considered. Various dissociation channels of HSiN and LiSiN and their isomers have been explored and an interesting trend has been observed for the dissociation of stable isomers HNSi and LiNSi and less stable isomers HSiN and LiSiN. The effect of substituents on dipole moment has been discussed. The potential energy surfaces for the RSiN ↔ RNSi isomerization reactions have been analyzed. The structural properties of these molecules agree well with the theoretical and experimental values wherever available.