中文摘要：

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.

英文摘要：

The heat of formation for 180 small-to medium-sized molecules was calculated by 20 kinds of theoretical methods.The results demonstrated that HF method showed the biggest deviation,therefore it generally should not be used;OLYP,B3PW91 and M05-2X methods had the minimum deviation in the GGA,Hybrid GGA and Hybrid meta-GGA methods,respectively.The calculated deviation of medium-size molecules was larger than that of small-size ones.The B3PW91 and M05-2X methods presented the minimum deviation for calculating small-and medium-size molecules,respectively.The calculated deviation of M05-2X method was more centralized than other methods.The calculated deviations of M05-2X,M06-2X,M06-HF and G4 methods mildly increased with increasing molecule size.