Quantum-chemical study of the adducts of silicon halides with nitrogen-containing donors:: II.: calculation of a donor-acceptor bond energy.: Complex trans-SiH4•2NH3

Structural and thermodynamic characteristics of the trans-SiH4 (.) 2NH(3) adduct were obtained by ab initio and DFT (RHF and B3LYP) calculations. Scanning the potential energy surface (PES) of the complex showed that its structure corresponds to a local minimum, whereas the global minimum corresponds to the free fragments. The energy of the silicon-nitrogen chemical bond was calculated with inclusion of fragment rearrangement energies and basis set superposition error. The procedure offered for calculating the Si-N bond energy was extended to adducts of silicon halides with ammonia. It was found that the energy of SiX4 rearrangement contributes most to the energies of donor-acceptor bonds in mono- and diammoniates of silicon tetrahalides.