Development of an intermolecular potential function for interactions in formamide clusters based on ab initio calculations
Development of an intermolecular potential function for interactions in formamide clusters based on ab initio calculations
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DOI：
10.1063/1.478582
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发表时间：
1999-04-08
影响因子：
4.4
通讯作者：
Ríos, MA
中科院分区：
文献类型：
--
作者：
Cabaleiro-Lago, EM;Ríos, MA
提出了一种描述甲酰胺分子间相互作用的势函数。该函数是从从头计算的分子性质和分子间微扰理论（IMPT）计算甲酰胺二聚体涉及6- 311 G ** 基组。它包括一个静电项，是一个函数的多极分布在原子上，一个指数排斥项通过拟合结果的二聚体，一个感应的贡献，是一个函数的原子极化率，和一个色散项的基础上的伦敦的表达，也依赖于原子极化率。甲酰胺二聚体应用所提出的功能得到的结果是类似的MP2/6- 311 G ** 水平上发现的功能，允许一个识别对应于尽可能多的能量最小值的五个结构。应用程序的功能较大的集群显示，最有吸引力的最小值对应于平面结构，其中最常见的结构模式是全球最小的二聚体。基于较大的簇的协同性数据，链状结构似乎形成更强的氢键，由于分子间相互作用的协同性增加，这可能是甲酰胺凝聚相采用开放结构的趋势。(C)1999年美国物理学会。
A potential function for describing interactions between formamide molecules is proposed. The function was developed from ab initio computed molecular properties and intermolecular perturbation theory (IMPT) calculations for formamide dimer involving the 6-311G** basis set. It consists of an electrostatic term that is a function of multipoles distributed over the atoms, an exponential repulsion term obtained by fitting results for the dimer, an induction contribution that is a function of atomic polarizabilities, and a dispersion term based on a London expression that is also dependent on atomic polarizabilities. The results obtained by applying the proposed function to formamide dimer are similar to those found at the MP2/6-311G** level; the function allows one to identify five structures corresponding to as many energy minima. Application of the function to larger clusters revealed that the most attractive minima correspond to planar structures, the most common structural pattern among which is that of the global minimum for the dimer. Based on cooperativeness data for the larger clusters, chained structures seemingly form stronger hydrogen bonds due to increased cooperativeness in interactions between molecules, which may account for the tendency of condensed phases of formamide to adopt open structures. (C) 1999 American Institute of Physics.