Khan Shumaila S, Yu Xinrui, Wade Jeffrey R, Malmgren R Dean, Broadbelt Linda J
Department of Chemical and Biological Engineering, Northwestern University, Evanston, Illinois 60208-3120, USA.
J Phys Chem A. 2009 Apr 30;113(17):5176-94. doi: 10.1021/jp809361y.
Thermochemistry of radicals is not as extensively tabulated as that of stable molecular species, even when group additivity schemes are applied. When these radicals contain oxygen or nitrogen atoms, the availability of radical groups is even more limited. Many oxygen- and nitrogen-containing radicals and molecules are present in the atmosphere, and thermochemistry is a valuable component of the development of atmospheric models with predictive capabilities. This paper presents quantum chemical calculations using G3//B3LYP that have been performed to obtain heats of formation, entropies, and heat capacities as a function of the temperature of radicals and molecules from which group additivity values were obtained. Isodesmic and homodesmotic reactions were used to obtain improved estimates of the heats of formation. Thermodynamic property estimates were corrected to account for internal rotations. A total of 323 molecules were studied from which a total of 122 different groups, 21 gauche and cis corrections, and 5 secondary corrections were regressed.
即使应用基团加和方案，自由基的热化学数据也不像稳定分子物种那样有广泛的列表。当这些自由基含有氧或氮原子时，自由基基团的可得性甚至更有限。大气中存在许多含氧化合物和含氮自由基及分子，热化学是开发具有预测能力的大气模型的重要组成部分。本文介绍了使用G3//B3LYP进行的量子化学计算，这些计算用于获得作为自由基和分子温度函数的生成热、熵和热容，从中得到基团加和值。使用等键反应和同键反应来改进生成热的估计。对热力学性质估计值进行了校正以考虑内旋转。总共研究了323个分子，从中回归得到了总共122个不同基团、21个gauche和顺式校正以及5个二级校正。
