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采用20种理论方法计算了180个中小型有机分子的生成热.结果表明:HF是最差的方法,一般不宜采用;OLYP,B3PW91和M05-2X分别是GGA,Hybrid GGA和Hybridmeta-GGA方法中计算偏差最小的一种方法;对于所有的计算方法,中型分子的计算偏差要大于小型分子的计算偏差;小型分子和中型分子计算偏差最小的方法分别是B3PW91和M05-2X;M05-2X所计算的偏差比其他方法集中;随着分子尺度的增加,M05-2X,M06-2X,M06-HF和经典G4方法所计算结果的偏差呈波浪型缓慢增加.
20 theoretical methods were used to calculate the heat of formation of 180 small and medium-sized organic molecules. The results showed that HF was the worst method and was not suitable for general use. OLYP, B3PW91 and M05-2X were the methods of GGA, Hybrid GGA and Hybridmeta-GGA For all calculation methods, the calculation deviation of medium molecules is larger than the calculation deviation of small molecules; The method of least deviation of small molecule and medium molecule calculation is B3PW91 and M05-2X; M05-2X The deviations of the calculated results from M05-2X, M06-2X, M06-HF and the classical G4 method show a slight increase in wave form as the molecular scale increases.