Theoretica chimica acta

, Volume 21, Issue 1, pp 1–8 | Cite as

Valence shell calculations on polyatomic molecules

IV. The effect of deorthogonalization on CNDO/2 dipole moments and charge distributions
  • D. D. Shillady
  • F. P. BillingsleyII
  • J. E. Bloor
Commentationes

Abstract

Dipole moments and charge distributions for twenty molecules of widely different types have been calculated using (a) the CNDO/2 method and (b) a CNDO/2D method in which the orbitals from the CNDO/2 method are deorthogonalized by a Löwdin transformation and are then used to calculate the dipole moments in a rigorous manner. A statistical analysis of the results for the dipole moments calculated by the CNDO/2D method shows that they are in very slightly better agreement with experiment than those from the CNDO/2 method. The net charge distributions from the CNDO/2D method follow more closely the trends of ab initio calculations than do the CNDO/2 net charges.

Keywords

Organic Chemistry Dipole Moment Charge Distribution Polyatomic Molecule Valence Shell 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Zusammenfassung

Dipolmomente und Ladungsdichten von Molekülen unterschiedlichen Typs wurden mittels des CNDO/2- und CNDO/2D-Verfahrens (d. i. mit delokalisierten Löwdin-Orbitalen als AO's) berechnet. Eine statistische Analyse zeigt, daß die Resultate der zweiten Methode etwas besser als die der ersten den experimentellen Ergebnissen folgen. Das Analoge gilt für die Nettoladungsverteilungen in bezug auf die Trends bei ab initio-Rechnungen.

Résumé

Les moments dipolaires et les distributions de charge pour vingt molécules de types divers ont été calculés par: a) la méthode CNDO/2; b) une méthode CNDO/2D où les orbitales de CNDO/2 sont déorthogonalisées par une transformation de Löwdin. Une analyse statistique montre que les moments dipolaires calculés par CNDO/2D sont légèrement en meilleur accord avec l'expérience que ceux calculés par CNDO/2. Les distributions de charge de CNDO/2D sont plus ressemblantes à celles de calculs ab-initio que ne le sont les distributions de CNDO/2.

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Copyright information

© Springer-Verlag 1971

Authors and Affiliations

  • D. D. Shillady
    • 1
  • F. P. BillingsleyII
    • 1
  • J. E. Bloor
    • 2
  1. 1.Department of ChemistryUniversity of VirginiaCharlottesville
  2. 2.Department of ChemistryUniversity of TennesseeKnoxville

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