PROPERTIES OF ATOMS IN MOLECULES - ATOMIC VOLUMES
PROPERTIES OF ATOMS IN MOLECULES - ATOMIC VOLUMES
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DOI：
10.1021/ja00260a006
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发表时间：
1987-12-23
影响因子：
15
通讯作者：
CHANG, C
中科院分区：
文献类型：
--
作者：
BADER, RFW;CARROLL, MT;CHANG, C
分子中的原子理论定义了原子及其性质的平均值。由电荷密度的性质定义的原子表面与电荷密度的特定包络的相交定义了分子中原子的体积。用来界定原子区域“开放”部分的密度包络值可以根据与测量性质的比较来选择。在任何情况下，结果的性质与对包含超过96%的总电子电荷并且位于通常的货车德瓦耳斯接触距离范围内的包封的选择无关。它表明，在正常的烃中的甲基和亚甲基的体积是可转移的性质，因为它们的电荷分布，人口和能量。空间拥挤的碳原子的体积被发现减少，其稳定性和电子布居的增加。这种行为与在环状和双环分子中发现的具有几何应变的系统中的碳原子的行为相反。碳原子的稳定性、布居数和体积都随着原子受到几何应变程度的增加而平行增加。双环[1.1]中桥头碳原子的体积。0]丁烷和[III]螺桨烷分别是甲基碳原子体积的1.2和1.5倍。正如在轨道模型的基础上所预期的那样，几何应变的增加与s特征的增加相关，因此人们发现碳原子的电子布居、稳定性和体积在乙烷、乙烯和乙炔的系列中经历相同的平行增加。作为研究原子如何结合在一起的第一步，确定伴随氢键形成的原子体积的变化。体积的变化与水和氨的同质和异质二聚体及其质子化物种的形成的原子布居和能量的变化相关。
The theory of atoms in molecules defines an atom and the average values of its properties. The intersection of an atomic surface, as defined by a property of the charge density, with a particular envelope of the charge density defines the volume of an atom in a molecule. The value of the density envelope used tobound the “open” portion of an atomic region can be chosen on the basis of comparison with measured properties. The nature of the results are, in any event, independent of the choice for envelopes which contain over 96% of the total electronic charge and lie within the usual range of van der Waals contact distances. It is shown that the volumes of methyland methylene groups in normal hydrocarbons are transferable properties, as are their charge distributions, populations, and energies. The volume of a carbon atom subject to steric crowding is found to decrease as its stability and electron population increase. This behavior is opposite to that found for a carbon atom in a system with geometric strain as found in cyclic and bicyclic molecules. The stability, population, and volume of a carbon atom all undergo parallel increases as the atom is subjected to an increasing degree of geometric strain. The volumes of the bridgehead carbon atoms in bicyclo [1.1. 0] butane and [lll] propellane are 1.2 and 1.5 times, respectively, the volume of a methyl carbon atom. As anticipated on the basis of the orbital model, an increase in geometric strain is correlated with an increase in s character and thus one finds the electron population, stability, and volume of a carbon atom to undergo the same parallel increases in value through the series ethane, ethylene, acetylene. As a first step in the investigation of how atoms fit together, the changes in the atomic volumes accompanying the formation of a hydrogen bond are determined. The changes in volume are correlated with the changes in the atomic populations and energies for the formationof homo and hetero dimers of water and ammonia and their protonated species.