Otlyotov Arseniy A, Minenkov Yury
N.N. Semenov Federal Research Center for Chemical Physics RAS, Moscow, Russian Federation.
Joint Institute for High Temperatures, Russian Academy of Sciences, Moscow, Russian Federation.
J Comput Chem. 2023 Aug 15;44(22):1807-1816. doi: 10.1002/jcc.27129. Epub 2023 May 9.
The experimental gas-phase thermochemistry of reactions: M (S) + S → M (S) and M + nS→ M (S) , where M is an alkali metal and S is acetonitrile/ammonia, is reproduced. Three approximations are tested: (1) scaled rigid-rotor-harmonic-oscillator (sRRHO); (2) the sRRHO(100) identical to (1), but with all vibrational frequencies smaller than 100 cm replaced with 100 cm ; (3) Grimme's modified scaled RRHO (msRRHO) (Grimme, Chem. Eur. J., 2012, 18, 9955-9964). The msRRHO approach provides the most accurate reaction entropies with the mean unsigned error (MUE) below 5.5 cal mol K followed by sRRHO(100) and sRRHO with MUEs of 7.2 and 16.9 cal mol K . For the first time, we propose using the msRRHO scheme to calculate the enthalpy contribution that is further utilized to arrive at reaction Gibbs free energies (∆G ) ensuring the internal consistency. The final ∆G MUEs for msRRHO, sRRHO(100) and sRRHO schemes are 1.2, 3.6 and 3.1 kcal mol .
对反应M (S) + S → M (S) 和M + nS→ M (S) 的实验气相热化学进行了再现，其中M为碱金属，S为乙腈/氨。测试了三种近似方法：(1) 标度刚性转子-谐振子 (sRRHO)；(2) 与(1)相同的sRRHO(100)，但所有小于100 cm的振动频率都替换为100 cm；(3) 格林姆改进的标度RRHO (msRRHO)（格林姆，《欧洲化学杂志》，2012年，18卷，9955 - 9964页）。msRRHO方法提供了最准确的反应熵，平均绝对误差 (MUE) 低于5.5 cal mol K，其次是sRRHO(100) 和sRRHO，MUE分别为7.2和16.9 cal mol K。我们首次提出使用msRRHO方案来计算焓贡献，该贡献进一步用于得出反应吉布斯自由能 (∆G )，以确保内部一致性。msRRHO、sRRHO(100) 和sRRHO方案的最终∆G MUE分别为1.2、3.6和3.1 kcal mol 。
