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做的东西是四个有机过氧化物,原子数十几到三四十个不等,优化和振动分析采用的是B3LYP/6-311+g(d,p),单点计算是M06-2X/def2-TZVP,本人接触量化不深,有三个问题不知如何回复,恳请大家帮忙看看,先谢谢大家!
1.In my opinion, the computational procedure isnot clear. How did you compute enthalpy and Gibbs energy at 298.15 K, B3LYP,M06-2X, or a combination? You said that you used M06-2X/def2-TZVP level for thesingle-point calculation. In general, the single-point calculation gives theelectronic energy (0 K) of the optimized structure. Enthalpy and Gibbs energycan be obtained by correcting the electron energy with the results of thefrequency analysis. I could not have understood this procedure. Could youexplain this in detail?
我对这个问题中提到的electronic energy (0 K)很疑惑,我计算单点的关键词是#P M06-2X/def2-TZVP, 得到的电子能量是0K下的吗?电子能量与温度有关系吗?
2.You said, "Relative electron energies,enthalpies, Gibbs free energies were calculated at standard conditions (298.15K, 1 atm)". What is the "electron energy at 298.15 K"? In myopinion, the "electron energy" is the energy at 0 K. How did youcalculate the effect of temperature?
这个问题是承接第一个问题的,不知是我一直以来理解错了,还是审稿人把电子能和零点能搞混了,恳请大家指点一二
3.The activation energy is an experimentallydetermined dependence of the reaction rate on temperature. On the other hand,delta E (0 or 298.15 K?) is a measure of the height of the electron energybarrier. I don't think we can make a simple comparison between the two, as theyare different physical quantities. Could you explain the relationship betweenapparent activation energy and electron energy barrier?
第三个问题是关于理论计算的能垒与实验活化能能否对应的。这个问题我知道自己应该用ΔG来讨论,但是用ΔG讨论不能很好的符合我实验得出的活化能的结果(四个有机过氧化物,活化能相差不大),相对电子能量与实验活化能相差了40kJ/mol左右,且定性结果与ΔG的结果一致(指能垒大小顺序一致),所以我就用了电子能量来讨论。现在面对审稿人的问题我不知该如何回答了,但是我心里有一个疑问,就是如果换成ΔG,这个能垒能否和实验活化能对比呢?如果可以,请问这样对比的依据是什么呢?有文献支撑相关观点吗?
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