Bond Ellipticity

2016 ◽  
Author(s):  
Vladimir I. Minkin
Keyword(s):  
Bond Ellipticity

Bond Ellipticity Alternation: An Accurate Descriptor of the Nonlinear Optical Properties of π-Conjugated Chromophores

2018 ◽  
Vol 9 (6) ◽  
pp. 1377-1383 ◽  
Author(s):  
Thiago O. Lopes ◽  
Daniel F. Scalabrini Machado ◽  
Chad Risko ◽  
Jean-Luc Brédas ◽  
Heibbe C. B. de Oliveira
Keyword(s):  
Optical Properties ◽  
Nonlinear Optical ◽  
Nonlinear Optical Properties ◽  
Bond Ellipticity

Universality among topological properties of electron density associated with the hydrogen–hydrogen nonbonding interactions

1992 ◽  
Vol 70 (2) ◽  
pp. 443-449 ◽  
Author(s):  
Jerzy Cioslowski ◽  
Stacey T. Mixon
Keyword(s):  
Electron Density ◽  
Functional Dependencies ◽  
Hydrogen Atoms ◽  
Topological Features ◽  
Second Derivatives ◽  
The Difference ◽  
Point Distance ◽  
Torsional Angles ◽  
Derivatives Of ◽  
Bond Ellipticity

Nonbonding repulsive interactions between hydrogen atoms, separated by less than ca. 2.18 Å and connected to two carbon atoms in the 1,4-positions, are associated with additional pairs of bond and ring critical points in the electron density, ρ(r), and the corresponding attractor interaction lines. Such topological features of ρ(r) are present in some planar benzenoid hydrocarbons, including chrysene, benzanthracene, and phenanthrene. They also appear in conformations of the biphenyl molecule with the torsional angles between the benzene rings lying within the range of 0°–27°. Properties such as the bond point – ring point distance, the difference in ρ(r) at the bond point and the ring point, and the bond ellipticity are found to follow universal functional dependencies with the hydrogen–hydrogen distance as the controlling variable. The same is true about the corresponding difference in the second derivatives of ρ(r) in the direction of the vector connecting the bond and ring points. Keywords: atoms in molecules, electron density, attractor interaction lines, steric repulsions.

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