A theoretical study of the reaction of N(4 S) with nitrogen dioxide on the N2O2 potential energy surface

Global and Full-Dimensional Potential Energy Surfaces of the N2 + O2 Reaction for Hyperthermal Collisions

“…As shown in Figure 20, N 2 and O 2 first undergo the transition states 1-TS 1 and 1-TS 2 to yield the same 1-vdW 1 , which corresponds to the O•••ON 2 complex. The energy of 1-TS 1 by the DSEC//UCCSD(T)-F12a/AVTZ method is 143.6 kcal mol −1 , significantly higher than 137.1 kcal mol −1 by UCCSD-(T)-F12a/AVDZ, 137.8 kcal mol −1 by UCCSD(T)-F12a/ AVTZ, or 139.5 kcal mol −1 by the CCSD(T)/cc-pVTZ// B3LYP/6-311++G(d, p) from Zuo et al 30 The values on the MB-PIP-NN, PIP-NN, and MB-PIP PESs are 141.1, 152.8, and 133.3 kcal mol −1 , respectively. At the UCCSD(T)-F12a/AVTZ level, 1-TS 2 is 18.6 kcal mol −1 lower in energy than 1-TS 1 .…”

“…Reaction Pathways. Zuo et al 30 mapped the reaction pathways on the triplet state of the N 2 O 2 system as early as 2012 and calculated the energies, structures, and frequencies at the CCSD(T)/cc-pVTZ//B3LYP/6-311++G(d, p) level. In this work, we further carried out high-precision calculations on the stationary points of the title system at the UCCSD(T)-F12a/ AVnZ (n = T, D) levels.…”

“…It is 120.0 kcal mol −1 by the DSEC method and 120.7 kcal mol −1 by the UCCSD(T)-F12a/ AVTZ method, and all three PESs are consistent with the ab initio values. For 1-vdW 1 , 1-TS 2 , and 1-TS 3 , the structure optimization by the UCCSD(T)-F12a method does not converge, so the geometry determined at the B3LYP/6-311+ +G(d,p) level by Zuo et al 30 was adopted for single-point energy calculations on the three PESs and by UCCSD(T)-F12a and DSEC. Note that the CCSD(T)/cc-pVTZ//B3LYP/6-311+ +G(d,p) results 30 may show large deviations from DSEC, UCCSD(T)-F12a/AVTZ, and three PESs and are thus not discussed further.…”

“…For 1-vdW 1 , 1-TS 2 , and 1-TS 3 , the structure optimization by the UCCSD(T)-F12a method does not converge, so the geometry determined at the B3LYP/6-311+ +G(d,p) level by Zuo et al 30 was adopted for single-point energy calculations on the three PESs and by UCCSD(T)-F12a and DSEC. Note that the CCSD(T)/cc-pVTZ//B3LYP/6-311+ +G(d,p) results 30 may show large deviations from DSEC, UCCSD(T)-F12a/AVTZ, and three PESs and are thus not discussed further. The three PESs deviate significantly from the DSEC values, for these transition states, intermediates, which may suggest the lack of sampling in these regions.…”

“…29 Then, the three PESs, MB-PIP, PIP-NN, and MB-PIP-NN, are analyzed and compared comprehensively. Note that the structures, frequencies, and energies of stationary points along the reaction pathways of the N 2 O 2 triplet state were reported in detail by Zuo et al 30 In this work, we also evaluated the performance of the three PESs on these stationary points with additional ab initio calculations. According to the evaluation, the global and full-dimensional high-precision ground-state triplet PES of the N 2 O 2 system can be corrected or even reconstructed.…”