以密度泛函理论表述的电负性及其均衡原理为基础,以组成原子电负性的调和平均为分子电负性参考取值,提出和设计了直接计算分子中原子电荷分布的新方案,避免了原算法中的多元回归和参数的多重选择,给出了分子环境下原子电负性和硬度的价...以密度泛函理论表述的电负性及其均衡原理为基础,以组成原子电负性的调和平均为分子电负性参考取值,提出和设计了直接计算分子中原子电荷分布的新方案,避免了原算法中的多元回归和参数的多重选择,给出了分子环境下原子电负性和硬度的价态标度.本方案能更简便广泛的应用于大分子中原子电荷分布的计算,结果与ab initio STO-3G的结果符合相当好.展开更多
On the basis of a more precise expression of the atomic effective electronegativity deduced from the density functional theory and electronegativity equalization principle, a new scheme for calculating the group elect...On the basis of a more precise expression of the atomic effective electronegativity deduced from the density functional theory and electronegativity equalization principle, a new scheme for calculating the group electronegativity and the atomic charges in a group is proposed and programed, and various parameters of electronegativity and hardness are given for some common atoms. Through calculation, analysis and comparison of more than one hundred groups, it is shown that the results from this scheme are reasonable and may be extended.展开更多
On the basis of electronegativity expressed in density functional theory and electronegativity equalization principle, a new scheme for calculating the atomic charges in a molecule has been proposed and designed, whic...On the basis of electronegativity expressed in density functional theory and electronegativity equalization principle, a new scheme for calculating the atomic charges in a molecule has been proposed and designed, which gives a new scale of the atomic electronegativity and hardness in a certain molecular environment and takes the harmonic mean electronegativity as a reference value of the molecular electronegativity so that the multiple-regression and nonuniform parameters in the original method are avoided. This approach can be easily and widely applied to the calculation of atomic charges for a big molecule and quite good results of atomic charges in some illustrated molecules are obtained as compared with those from the ab initio STO-3G SCF calculations.展开更多
The concept of electronegativity (EN) proposed by Pauling describes the power of an atom attracting electrons, and is widely used in discussing various properties of a molecule. However, its precise definition is only...The concept of electronegativity (EN) proposed by Pauling describes the power of an atom attracting electrons, and is widely used in discussing various properties of a molecule. However, its precise definition is only recently stated by Parr in terms of the density functional theory (DFT), which develops its study and application in many areas. In this decade, by use of the Sanderson’s electronegativity equalization principle (EEP), the direct calculation of atomic charges in a molecule is of great interest. There is a close relationship between the atomic charge distribution in a molecule and the molecular EN which are two important indices in chemistry. The former denotes the local property and the latter denotes the global property in a molecule. Since ab initio or various semi-empirical molecular orbital methods cannot展开更多
文摘以密度泛函理论表述的电负性及其均衡原理为基础,以组成原子电负性的调和平均为分子电负性参考取值,提出和设计了直接计算分子中原子电荷分布的新方案,避免了原算法中的多元回归和参数的多重选择,给出了分子环境下原子电负性和硬度的价态标度.本方案能更简便广泛的应用于大分子中原子电荷分布的计算,结果与ab initio STO-3G的结果符合相当好.
基金Project supported by the National Natural Science Foundation of Chinathe Foundation of State Education Commission of China
文摘On the basis of a more precise expression of the atomic effective electronegativity deduced from the density functional theory and electronegativity equalization principle, a new scheme for calculating the group electronegativity and the atomic charges in a group is proposed and programed, and various parameters of electronegativity and hardness are given for some common atoms. Through calculation, analysis and comparison of more than one hundred groups, it is shown that the results from this scheme are reasonable and may be extended.
基金Project supported by the National Natural Science Foundation of China.
文摘On the basis of electronegativity expressed in density functional theory and electronegativity equalization principle, a new scheme for calculating the atomic charges in a molecule has been proposed and designed, which gives a new scale of the atomic electronegativity and hardness in a certain molecular environment and takes the harmonic mean electronegativity as a reference value of the molecular electronegativity so that the multiple-regression and nonuniform parameters in the original method are avoided. This approach can be easily and widely applied to the calculation of atomic charges for a big molecule and quite good results of atomic charges in some illustrated molecules are obtained as compared with those from the ab initio STO-3G SCF calculations.
文摘The concept of electronegativity (EN) proposed by Pauling describes the power of an atom attracting electrons, and is widely used in discussing various properties of a molecule. However, its precise definition is only recently stated by Parr in terms of the density functional theory (DFT), which develops its study and application in many areas. In this decade, by use of the Sanderson’s electronegativity equalization principle (EEP), the direct calculation of atomic charges in a molecule is of great interest. There is a close relationship between the atomic charge distribution in a molecule and the molecular EN which are two important indices in chemistry. The former denotes the local property and the latter denotes the global property in a molecule. Since ab initio or various semi-empirical molecular orbital methods cannot
