The spin-forbidden quenching reaction, O(1D) + N2(X1Σg+) → N2(X1Σg+) + O(3P), has been studied by ab initio molecular orbital theory using different methods including CCSDTQ/CBS(TQ5)//CCSD(T)/aug-cc-pV5Z, whose energies were utilized for establishment of the singlet–triplet potential energy surface and prediction of thermal rate coefficients. The O(3P) + N2 formation via the long-lived singlet 1N2O intermediate has been identified to be dominant for the spin-forbidden crossing at the crossing point located at 60.3 kcal mol−1 above 1N2O, in good accordance with the literature values. The P,T-dependent rate constants predicted by the non-adiabatic RRKM theory agree closely with available results reported in the temperature range 50 – 700 K, over the pressure range of 1 – 250 Torr.
- Quenching rate constants
- Spin-forbidden surface