AB-INITIO STUDY OF THE ISOMERS - HNNSI, HSINN, AND HNSIN

We report on new structural, energetics, and vibrational frequency dat a for three isomers on the potential energy surface [H, Si, N, N] calc ulated at the UHF, MP2, and CCSD(T)/6-311G(2d) levels of theory. Simil arly to SiNN, conventional methods fail to predict a thermodynamic sta bility for the isomer HSiNN. However, at the CCSD(T) level, the specie s HSiNN was found to Lie 13.63 kcal mol(-1) lower in energy than HNNSi ; the isomer HNSiN was located 47.62 kcal mol(-1) above the global min imum. After including the zero-point energy corrections, the isomer HS iNN becomes almost isoenergetic with its dissociation products HSi and N-2; its detection might be likely only at low temperatures.