The spin‐forbidden dissociation reaction of the N₂O(X¹Σ⁺) ground state has been investigated by both quantum calculations and experiments. Ab initio prediction at the CCSD(T)/CBS(TQ5)//CCSD(T)/aug‐cc‐pVTZ+d level of theory gave the crossing point (MSX) energy at 60.1 kcal/mol for the N₂O(X¹Σ⁺) → N₂() + O(³P) transition, in good agreement with published data. The T‐ and P‐dependent rate coefficients, k₁(T,P), for the nonadiabatic thermal dissociation predicted by nonadiabatic Rice‐Ramsperger‐Kassel‐Marcus (RRKM) calculations agree very well with literature data. The rate constants at the high‐ and low‐pressure limits, k₁^∞ = 10^11.90 exp (−61.54 kcal mol⁻¹/RT) s⁻¹ and k₁^o = 10^14.97 exp(−60.05 kcal mol⁻¹/RT) cm³ mol⁻¹ s⁻¹, for example, agree closely with the extrapolated results of Röhrig et al. at both pressure limits. The second‐order rate constant (k₁^o) is also in excellent agreement with our result measured by FTIR spectrometry in the present study for the temperature range of 860‐1023 K as well as with many existing high‐temperature data obtained primarily by shock‐wave heating up to 3340 K. Kinetic modeling of the NO product yields measured at long reaction times in the present work also allowed us to reliably estimate the rate constant for reaction (3), O + N₂O → N₂ + O₂, based on its strong competition with the NO formation from reaction (2) which has been better established. The modeled values of k₃ confirmed the previous finding by Davidson et al. with significantly smaller values of A‐factor and activation energy than the accepted ones. A least‐squares analysis of both sets of data gave k₃ = 10^{12.22 ± 0.04} exp[− (11.65 ± 0.24 kcal mol⁻¹/RT)] cm³ mol⁻¹ s⁻¹, covering the wide temperature range of 988‐3340 K.

中文翻译：

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FTIR光谱研究900 K附近N2O的热分解：实验和理论O（3P）形成动力学的比较

所述N个的自旋禁阻离解反应₂ O（X ¹ Σ ⁺）基态已通过两个量子计算和实验研究。在CCSD（T）/ CBS（TQ5）// CCSD（T）/ aug-cc-pVTZ + d理论水平的从头算预测得出N ₂ O（60.1 kcal / mol）的交叉点（MSX）能量X ¹ Σ ⁺）→ñ ₂（）+ O（³ P）过渡，与公开的数据一致。由T和P决定的速率系数k ₁（T，P），对于非绝热的Rice-Ramsperger-Kassel-Marcus（RRKM）预测的非绝热热解与文献数据非常吻合。在高和低压力极限的速率常数，ķ ₁ ^∞  = 10 ^11.90实验值（-61.54千卡摩尔^-1 / RT）■ ^-1和ķ ₁ ^ö  = 10 ^14.97实验值（-60.05千卡摩尔^-1 / RT）cm ³ mol ^-1 s ^-1，例如，与Röhrig等人的推断结果非常吻合。在两个压力极限下。二阶速率常数（k ₁^o）也与我们在本研究中通过FTIR光谱法在860-1023 K的温度范围内测量的结果以及主要通过冲击波加热到3340 K的温度获得的许多现有高温数据非常吻合。在本研究中，通过长时间反应测量的NO产物产率的模型化模型，也使我们能够可靠地估计反应（3）的速率常数，即O + N ₂ O→N ₂ + O ₂，因为它与NO竞争激烈由反应（2）形成，已被更好地确定。k ₃的模型值证实了Davidson等人的先前发现。具有明显较小的A值因子和活化能比公认的高。两组数据的最小二乘分析得出k ₃  = 10 ^12.22±0.04 exp [-（（11.65±0.24 kcal mol ^-1 / RT）] cm ³ mol ^-1 s ^-1，覆盖了988-的宽温度范围3340千。