Experimental and Modelling Study of the Unimolecular Thermal Decompostion of CHF3
Experimental and Modelling Study of the Unimolecular Thermal Decompostion of CHF3
复制标题
CHF3单分子热分解实验与模拟研究
DOI：
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发表时间：
2011
期刊：
影响因子：
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通讯作者：
Hans
中科院分区：
文献类型：
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作者：
C. Cobos;A. E. Croce;K. Luther;Hans
摘要通过监测CF2自由基形成过程的紫外吸收，研究了激波下CHF3 （+M）→CF2 + HF （+M）的单分子热分解反应。从单分子速率理论的角度，分析了目前和以往关于速率常数与温度和压力的关系的实验结果。衰减曲线（1500-1900 K）的拟合极限低压速率常数k0 = [Ar] 1.1 × 1016exp(- 53.0 kcal mol - 1/RT) cm3mol - 1s - 1，极限高压速率常数K∞= 1.25 × 1015 exp(- 75.8 kcal mol - 1/RT) s - 1，中心展宽因子Fcent = 0.170（±0.04），包括单分子速率理论的强碰撞和弱碰撞贡献。利用这些结果，衰减曲线的近似解析表达式很好地表示了在很宽的压力和温度范围内测量和计算的速率常数。
Abstract The unimolecular thermal decomposition reaction CHF3 (+M)→CF2 + HF (+M) was studied in shock waves by monitoring the UV absorption of the forming CF2 radicals. The results of the present and previous experiments on the temperature and pressure dependence of the rate constants are analyzed in terms of unimolecular rate theory. Falloff curves (for 1500–1900 K) are represented in terms of fitted limiting low pressure rate constants k0 = [Ar] 1.1 × 1016exp(−53.0 kcal mol−1/RT) cm3mol−1s−1, limiting high pressure rate constants k∞ = 1.25 × 1015 exp(−75.8 kcal mol−1/RT) s−1 from quantum-chemical calculations, and center broadening factors Fcent = 0.170(± 0.04) including strong and weak collision contributions from unimolecular rate theory. With these results, approximate analytical expressions of the falloff curves well represent the measured and calculated rate constants over wide ranges of pressure and temperature.