Zhu R S, Lin M C
Department of Chemistry, Emory University, 1515 Dickey, Drive, Atlanta, GA 30322, USA.
Chemphyschem. 2005 Aug 12;6(8):1514-21. doi: 10.1002/cphc.200400448.
The potential-energy surface for the reaction of ClO with NO2 has been constructed at the CCSD(T)/6-311+G(3df)//B3LYP/6-311+G(3df) level of theory. Six ClNO3 isomers are located; these are ClONO2, pc-ClOONO, pt-ClOONO, OClNO2, pt-OClONO, pc-OClONO, with predicted energies relative to the reactants of -25.6, -0.5, 1.0, 1.9, 12.2 and 13.6 kcal mol-1, and heats of formation at 0 K of 7.8, 32.9, 34.4, 35.5, 45.6 and 47.0 kcal mol-1, respectively. Isomerizations among them are also discussed. The rate constants for the low-energy pathways have been computed by statistical theory calculations. For the association reaction producing exclusively ClONO2, the predicted low- and high-pressure-limit rate constants in N2 for the temperature range of 200-600 K can be represented by: (N2)=3.19 x 10-17 T-5.54 exp(-384 K/T) cm6 molecule-2 s-1 and =3.33 x 10-7 T-1.48 exp(-18 K/T) cm3 molecule-1 s-1. The predicted low- and high-pressure-limit rate constants for the decomposition of ClONO2 in N2 at 200-600 K can be expressed, respectively, by =6.08 x 1013 T-6.54 exp(-13813 K/T) cm3 molecule-1 s-1 and =4.59 x 1023 T-2.43 exp(-13437 K/T) s-1. The predicted values compare satisfactorily with available experimental data. The reverse Cl+NO3 reaction was found to be independent of the pressure, giving exclusively ClO+NO2; the predicted rate constant can be expressed as k(Cl+NO3)=1.19 x 10-9 T-0.60 exp(58 K/T) cm3 molecule-1 s-1..
在CCSD(T)/6-311+G(3df)//B3LYP/6-311+G(3df)理论水平下构建了ClO与NO₂反应的势能面。确定了六种ClNO₃异构体；它们分别是ClONO₂、对位-ClOONO、邻位-ClOONO、OClNO₂、邻位-OClONO、对位-OClONO，相对于反应物的预测能量分别为-25.6、-0.5、1.0、1.9、12.2和13.6千卡/摩尔，0K时的生成热分别为7.8、32.9、34.4、35.5、45.6和47.0千卡/摩尔。还讨论了它们之间的异构化。通过统计理论计算得到了低能反应途径的速率常数。对于仅生成ClONO₂的缔合反应，在200-600K温度范围内，N₂中预测的低压和高压极限速率常数可表示为：k₁(N₂)=3.19×10⁻¹⁷T⁻⁵.⁵⁴exp(-384K/T)厘米⁶分子⁻²秒⁻¹，k₂=3.33×10⁻⁷T⁻¹.⁴⁸exp(-18K/T)厘米³分子⁻¹秒⁻¹。在200-600K温度范围内，N₂中ClONO₂分解的预测低压和高压极限速率常数分别可表示为：k₃=6.08×10¹³T⁻⁶.⁵⁴exp(-13813K/T)厘米³分子⁻¹秒⁻¹，k₄=4.59×10²³T⁻².⁴³exp(-13437K/T)秒⁻¹。预测值与现有实验数据比较吻合。发现反向Cl+NO₃反应与压力无关，仅生成ClO+NO₂；预测的速率常数可表示为k(Cl+NO₃)=1.19×10⁻⁹T⁻⁰.⁶⁰exp(58K/T)厘米³分子⁻¹秒⁻¹。
