【作者】 牛春莹；

【导师】 杨忠志；

【作者基本信息】 辽宁师范大学 ， 物理化学， 2002， 硕士

【摘要】 铁卟啉分子在生物体内起着十分重要的作用。人们熟知的进行氧传递作用的血红蛋白、氧活化和电子传递的细胞色素C和细胞色素P-450都是金属铁卟啉系列。由于分子中的电荷分布与分子的性质息息相关，计算铁卟啉化合物的电荷分布就显得非常重要。 由于传统的从头计算方法所需要的计算量太大，很难应用到大的分子体系。因此，发展准确的、计算上易于实行的方法用于探讨大分子的性质是现在理论化学的重要任务。我们以密度泛函理论[1-4]和电负性均衡原理[5-9]为基础，应用和开发了原子-键电负性均衡模型（ABEEM）。利用最小二乘法拟合确定了一些分子的各种类型原子及化学键区域的参数。运用这些参数，计算了有关铁卟啉分子的电荷分布以及分子的总能量，其得到的结果可以和从头计算相媲美,并且计算所需要的时间与从头计算相比非常短。更多还原

【Abstract】 The calculation of charge distribution in iron porphyrins Iron porphyrins play an important role in organism. People are familiar with iron porphyrins including hemoglobin of transferring oxygen, cytochrome C and cytochrom P-450. Since molecular charge distribution is closely related to molecular properties, it is important to calculate charge distribution of iron porphyrin compound. Conventional ab initio methods are hard to apply to the large molecular systems, so developing an accurate and economic method to probe the relationship between structures and properties of large molecules is a promising research area in nowadays theoretical chemistry. We have proposed an atom-bond electronegativity equalization model(ABEEM) on the basis of density functional theory and electronegativity equalization principle. Using separated program, through regression and least-squares optimization, the parameters of atoms and bonds in molecules are determined. By these parameters, the charge distributions and the energy of iron porphyrins are calculated. The time of calculation is short and the results are good.更多还原