Reaction of Cl with N3: a CAS study

The CAS methods were used for exploring mechanisms of the Cl + N3(X2Π) → NCl(1Δ) + N2 (i) and Cl + N3(X2Π) → NCl(X3Σ−) + N2 (ii) reactions. The CASSCF/cc- pVTZ path calculations indicate that channel (i) occurs in the 1A′ potential energy surface (PES) and there exists an intermediate (IM(1A′)) followed by a transition state along the reaction path and that channel (ii) occurs in the 3A′′ PES and it has a single step with a transition state. The CASPT2/cc-pVTZ energetic results indicate that channel (i) is feasible while channel (ii) is unfeasible. Preliminary exploration for the 1A′–3A′′ PES crossing at the CASSCF/cc-pVTZ level implies that the crossing may not cause predissociation of IM(1A′) into the ground state product (NCl (3Σ−) + N2).