ABINITIO STUDY OF THE ENERGETICS OF THE SPIN-ALLOWED AND SPIN-FORBIDDEN DECOMPOSITION OF HN3

We describe an investigation of the energetics of the dissociation of ground state hydrazoic acid HN3. The study is limited to the lowest energy spin-allowed and spin-forbidden decomposition pathways, namely HN 3(X̃ 1A′) → N2(X 1Σg+) + NH(a 1Δ,X 3σ) and HN3(X̃ 1A′) → N3(X̃ 2Πg) + H(2S). Complete active space SCF and multireference configuration interaction calculations with large basis sets are used (a) to determine the NNN-H and NN-NH bond dissociation energies of HN3, (b) to locate the geometry of the transition state for the spin-forbidden decomposition and the corresponding activation energy, and (c) to investigate the magnitude and origin of the exit channel barrier in the spin-allowed decomposition channel. © 1990 American Institute of Physics.