Properties of atoms in molecules. I. Proposed definition of the charge on an atom in a molecule
01 Nov 1970-Journal of the American Chemical Society (American Chemical Society)-Vol. 92, Iss: 22, pp 6451-6454
About: This article is published in Journal of the American Chemical Society.The article was published on 1970-11-01. It has received 155 citations till now. The article focuses on the topics: 1s Slater-type function & Atoms in molecules.
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TL;DR: In this article, a general and natural choice is to share the charge density at each point among the several atoms in proportion to their free-atom densities at the corresponding distances from the nuclei.
Abstract: For quantitative description of a molecular charge distribution it is convenient to dissect the molecule into well-defined atomic fragments. A general and natural choice is to share the charge density at each point among the several atoms in proportion to their free-atom densities at the corresponding distances from the nuclei. This prescription yields well-localized bonded-atom distributions each of which closely resembles the molecular density in its vicinity. Integration of the atomic deformation densities — bonded minus free atoms — defines net atomic charges and multipole moments which concisely summarize the molecular charge reorganization. They permit calculation of the external electrostatic potential and of the interaction energy between molecules or between parts of the same molecule. Sample results for several molecules indicate a high transferability of net atomic charges and moments.
5,234 citations
TL;DR: In this article, a method for the rapid calculation of atomic charges in σ-bonded and nonconjugated π-systems is presented, where only the connectivities of the atoms are considered.
3,640 citations
TL;DR: An explanation for its occurrence in terms of a region of positive electrostatic potential present on the outermost portions of some covalently-bonded halogen atoms is presented.
Abstract: Halogen bonding (XB) is a type of noncovalent interaction between a halogen atom X in one molecule and a negative site in another. X can be chlorine, bromine or iodine. The strength of the interaction increases in the order Cl
1,241 citations
TL;DR: In this paper, a new algorithm for fitting atomic charges to molecular electrostatic potentials is presented, which is non-iterative and rapid compared to previous work. But this method is not suitable for a large number of atoms and anions, and the effects of using experimental and optimized geometries are explored.
Abstract: A new algorithm for fitting atomic charges to molecular electrostatic potentials is presented. This method is non-iterative and rapid compared to previous work. Results from a variety of gaussian basis sets, including STO-3G, 3-21G and 6-31G*, are presented. Charges for a representative collection of molecules, comprising both first and second row atoms and anions are tabulated. The effects of using experimental and optimized geometries are explored. Charges derived from these fits are found to adequately reproduce SCF dipole moments. A small split valence representation, 3-21G, appears to yield consistently good results in a reasonable amount of time.
974 citations
TL;DR: The Voronoi Deformation Density (VDD) method for computing atomic charges does not explicitly use the basis functions but calculates the amount of electronic density that flows to or from a certain atom due to bond formation by spatial integration of the deformation density over the atomic Vor onoi cell.
Abstract: We present the Voronoi Deformation Density (VDD) method for computing atomic charges. The VDD method does not explicitly use the basis functions but calculates the amount of electronic density that flows to or from a certain atom due to bond formation by spatial integration of the deformation density over the atomic Voronoi cell. We compare our method to the well-known Mulliken, Hirshfeld, Bader, and Weinhold [Natural Population Analysis (NPA)] charges for a variety of biological, organic, and inorganic molecules. The Mulliken charges are (again) shown to be useless due to heavy basis set dependency, and the Bader charges (and often also the NPA charges) are not realistic, yielding too extreme values that suggest much ionic character even in the case of covalent bonds. The Hirshfeld and VDD charges, which prove to be numerically very similar, are to be recommended because they yield chemically meaningful charges. We stress the need to use spatial integration over an atomic domain to get rid of basis set dependency, and the need to integrate the deformation density in order to obtain a realistic picture of the charge rearrangement upon bonding. An asset of the VDD charges is the transparency of the approach owing to the simple geometric partitioning of space. The deformation density based charges prove to conform to chemical experience.
918 citations