半经验的自洽场分子轨道法(AM1)被用来研究激发单态(~1ππ~*)和三态(~3ππ~*)丙烯酸的脱羧反应.计算结果支持Robert 等人提出的光解机理.与实验结合.进一步推测,丙烯酸光致脱羧反应的第一步,是沿单态途径进行,第二步沿三态途径进行.单态和三态反应途径中的反应物、过渡态、中间体和产物都用能量梯度技术进行了优化.对于过渡态和中间体,还作了振动分析,确证它们分别是一级鞍点和能量极小值点. Semi-empirical self-consistent field-based molecular orbital method (AM1) was used to study the decarboxylation of excited singlet (~ 1ππ ~ *) and tristate (~ 3ππ ~ *) acrylic acid. The results support the photolysis mechanism proposed by Robert et al. . Combining with the experiment, it is further speculated that the first step in the photo-induced decarboxylation of acrylic acid is along the monomorphic pathway and the second along the three-state pathway.The reactants, transition states, intermediate Both the bulk and the product were optimized by the energy gradient technique. For the transition states and intermediates, vibration analysis was also done to verify that they are the first-order saddle point and the second-smallest energy point, respectively.