Topological Atomic Charges, Valencies, and Bond Orders

1995 ◽  
Vol 35 (3) ◽  
pp. 383-395 ◽  
Author(s):  
Danail Bonchev ◽  
Ekaterina Gordeeva
Keyword(s):  
Atomic Charges ◽  
Bond Orders

scholarly journals Introducing DDEC6 atomic population analysis: part 4. Efficient parallel computation of net atomic charges, atomic spin moments, bond orders, and more

RSC Advances ◽  
2018 ◽  
Vol 8 (5) ◽  
pp. 2678-2707 ◽  
Author(s):  
Nidia Gabaldon Limas ◽  
Thomas A. Manz
Keyword(s):  
Parallel Computation ◽  
Population Analysis ◽  
Atomic Charges ◽  
Bond Orders ◽  
Atomic Spin ◽  
Spin Moments

We parallelize the DDEC6 method to efficiently compute net atomic charges, atomic spin moments, and bond orders in diverse materials.

scholarly journals Atomic Charges, Surface Electrostatic Potential Analysis, and Bond Order Analysis on Nitriles and Isocyanides

2021 ◽  
Author(s):  
Yanyun Zhao ◽  
Xueli Cheng
Keyword(s):  
Electrostatic Potential ◽  
Bond Order ◽  
Atomic Charges ◽  
Bond Orders ◽  
Potential Analysis ◽  
Order Analysis ◽  
Population Analyses ◽  
Full Optimization ◽  
Global And Local ◽  
Surface Electrostatic Potential

Abstract Isocyanide-nitrile rearrangement has long been a continuing and interesting topic. A series of nitriles and isocyanides with the substituents of R=-AlH2, -BeH, -BH2, -C ≡ CH, -CF3, -CH3, -Cl, -C ≡ N, -COOH, -F, -H, Li, -MgH, -Na, -NH2, -NO2, -OH, -PH2, -SH, -SiH3, -CH = CH2 were investigated systematically based on full optimization at B3LYP-D3(BJ)/def2-QZVP level, and the isomerization energies from R-C ≡ N to :C = N-R were estimated. The substituent effect and bonding characters were analyzed by surface ESP colored van der Waals surfaces in conjunction with the global and local electrostatic extrema, the population analyses in terms of Hirshfeld and ADCH atomic charges, and bond order analyses via Laplacian and fuzzy bond orders.

A Correlation between Bond Length and Ionic Bond Order. Application to the Ylide–Ylene Problem

1975 ◽  
Vol 53 (20) ◽  
pp. 3040-3043 ◽  
Author(s):  
Myung-Hwan Whangbo ◽  
Saul Wolfe ◽  
Fernando Bernardi
Keyword(s):  
Bond Length ◽  
Bond Order ◽  
The Other ◽  
Atomic Charges ◽  
Bond Orders ◽  
Ionic Bond ◽  
Molecular Systems ◽  
Bond Lengths ◽  
Coulombic Repulsion ◽  
Overlap Population

The C—O and C—S bond lengths of the cations, radicals, and anions CH3O, CH3S, CH2OH, and CH2SH have been found not to correlate with the overlap populations of the C—X bonds. On the other hand, very satisfactory linear relations are observed with the ionic bond orders of the C—X bonds. It is suggested that, in certain molecular systems, it may be more meaningful to associate shortening of a bond A—B with greater coulombic attraction (or smaller coulombic repulsion) between the two point charges represented by the net atomic charges on the atoms A and B than with an increase in the overlap population between these atoms. It is noted that such an interpretation can account for the short C—P bond in a phosphonium ylide without resort to (p → d)π conjugation.

scholarly journals A Generalized Omega-Technique for Molecular Orbital Calculations

1979 ◽  
Vol 34 (11) ◽  
pp. 1365-1368 ◽  
Author(s):  
Francisco M. Fernández ◽  
Eduardo A. Castro
Keyword(s):  
Molecular Structures ◽  
Electronic Transitions ◽  
Hamiltonian Matrix ◽  
Molecular Orbital Calculations ◽  
Atomic Charges ◽  
Bond Orders ◽  
Matrix Elements ◽  
Hartree Fock ◽  
Electron Repulsion Integrals ◽  
Natural Way

A derivation of the omega-like methods to calculate electronic molecular structures is given. The derivation is based on t h e Hartree-Fock formalism and shows in a natural way how the omega-like methods follows through the retention of certain two-electron repulsion integrals and the neglection of other ones. A generalized omega-technique is proposed where both diagonal and non-diagonal Hamiltonian matrix elements depend on atomic charges a n d bond orders. Some numerical examples are presented for the calculation of bond lengths, ionization potentials and VI ← N electronic transitions

Can we treat ab initio atomic charges and bond orders as conformation-independent electronic structure descriptors?

RSC Advances ◽  
2016 ◽  
Vol 6 (78) ◽  
pp. 74785-74796 ◽  
Author(s):  
T. Yu. Nikolaienko ◽  
L. A. Bulavin ◽  
D. M. Hovorun
Keyword(s):  
Electronic Structure ◽  
Ab Initio ◽  
Atomic Charges ◽  
Bond Orders ◽  
Molecule Conformation

It is shown that atomic charges and bond orders of 2′-deoxycytidine depend on the molecule conformation.

Hydration Free Energies of Organic Molecules in the FreeSolv Database Calculated with Polarized Atom In Molecules Atomic Charges and the GAFF Force Field.

2018 ◽  
Author(s):  
Maximiliano Riquelme ◽  
Alejandro Lara ◽  
David L. Mobley ◽  
Toon Vestraelen ◽  
Adelio R Matamala ◽  
...  
Keyword(s):  
Force Field ◽  
Functional Groups ◽  
Electrostatic Interactions ◽  
Organic Molecules ◽  
Force Fields ◽  
Chemical Elements ◽  
Atomic Charges ◽  
Free Energies ◽  
Molecular Systems ◽  
Solvent Model

<div>Computer simulations of bio-molecular systems often use force fields, which are combinations of simple empirical atom-based functions to describe the molecular interactions. Even though polarizable force fields give a more detailed description of intermolecular interactions, nonpolarizable force fields, developed several decades ago, are often still preferred because of their reduced computation cost. Electrostatic interactions play a major role in bio-molecular systems and are therein described by atomic point charges.</div><div>In this work, we address the performance of different atomic charges to reproduce experimental hydration free energies in the FreeSolv database in combination with the GAFF force field. Atomic charges were calculated by two atoms-in-molecules approaches, Hirshfeld-I and Minimal Basis Iterative Stockholder (MBIS). To account for polarization effects, the charges were derived from the solute's electron density computed with an implicit solvent model and the energy required to polarize the solute was added to the free energy cycle. The calculated hydration free energies were analyzed with an error model, revealing systematic errors associated with specific functional groups or chemical elements. The best agreement with the experimental data is observed for the MBIS atomic charge method, including the solvent polarization, with a root mean square error of 2.0 kcal mol<sup>-1</sup> for the 613 organic molecules studied. The largest deviation was observed for phosphor-containing molecules and the molecules with amide, ester and amine functional groups.</div>

Sign in / Sign up

Export Citation Format

Share Document