Determination of partial atomic charges from ab initio molecular electrostatic potentials. Application to formamide, methanol, and formic acid

1978 ◽  
Vol 82 (5) ◽  
pp. 592-601 ◽  
Author(s):  
Frank A. Momany
Keyword(s):  
Formic Acid ◽  
Ab Initio ◽  
Electrostatic Potentials ◽  
Atomic Charges ◽  
Molecular Electrostatic Potentials ◽  
Partial Atomic Charges

Anomalous stabilizing and destabilizing effects in some cyclic π-electron systems

1993 ◽  
Vol 71 (8) ◽  
pp. 1123-1127 ◽  
Author(s):  
Peter Politzer ◽  
M. Edward Grice ◽  
Jane S. Murray ◽  
Jorge M. Seminario
Keyword(s):  
Ab Initio ◽  
Lone Pair ◽  
Electrostatic Potentials ◽  
Electron Delocalization ◽  
Isodesmic Reaction ◽  
Computational Studies ◽  
Electron Systems ◽  
Molecular Electrostatic Potentials ◽  
Lone Pairs

Ab initio computational studies have been carried out for three molecules that are commonly classed as antiaromatic: cyclobutadiene (1), 1,3-diazacyclobutadiene (7), and 1,4-dihydropyrazine (6). Their dinitro and diamino derivatives were also investigated. Stabilizing or destabilizing energetic effects were quantified by means of the isodesmic reaction procedure at the MP2/6-31G*//HF/3-21G level, and calculated molecular electrostatic potentials (HF/STO-5G//HF/3-21G) were used as a probe of electron delocalization. Our results do not show extensive delocalization in the π systems of any one of the three parent molecules. The destabilization found for 1 and 7 is attributed primarily to strain and to repulsion between the localized π electrons in the C=C and C=N bonds, respectively. However, 6 is significantly stabilized, presumably due to limited delocalization of the nitrogen lone pairs. NH2 groups are highly stabilizing, apparently because of lone pair delocalization. NO2 is neither uniformly stabilizing nor destabilizing.

Ab initio counterpart of infrared atomic charges. Comparison with charges obtained from electrostatic potentials

1988 ◽  
Vol 151 (4-5) ◽  
pp. 397-402 ◽  
Author(s):  
M.N. Ramos ◽  
M. Gussoni ◽  
C. Castiglioni ◽  
G. Zerbi
Keyword(s):  
Ab Initio ◽  
Electrostatic Potentials ◽  
Atomic Charges

On the Calculation of the Electrostatic Potentials at the Nuclei in the Point-charge Approximation

1983 ◽  
Vol 38 (3) ◽  
pp. 308-312 ◽  
Author(s):  
Z. B. Maksić ◽  
K. Rupnik
Keyword(s):  
Ab Initio ◽  
Point Charge ◽  
Atomic Charge ◽  
Electrostatic Potentials ◽  
Molecular Properties ◽  
Atomic Charges ◽  
Self Consistent

Abstract It is shown that the concept of atomic charge in molecules is a useful tool in studying electrostatic potentials at the nuclei which in turn are closely related to a number of molecular properties. Calculations executed on a selected set of widely different compounds provide extensive evidence that the semiempirical SCC-MO (self-consistent charge) atomic charges are equally successful in this respect as the ab initio DZ ones.

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