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Approaches to charge calculations in molecular mechanics

✍ Scribed by Raymond J. Abraham; Lee Griffiths; Philip Loftus

Publisher
John Wiley and Sons
Year
1982
Tongue
English
Weight
895 KB
Volume
3
Category
Article
ISSN
0192-8651

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✦ Synopsis

Abstract

Alternative methods of estimating atomic charges in haloalkanes are presented, derived from quantum mechanical and classical treatments. A scheme based on a breakdown of the transmission of charge by polar atoms into one‐bond, two‐bond, and three‐bond additive contributions is given, in which the one‐bond effect is proportional to the difference in the electronegativities of the bonded atoms, and the two‐ and three‐bond effects functions of the atomic electronegativity and polarizability. Suitable developments of the basic scheme, including an iterative self‐consistent process, give calculated dipole moments for a variety of haloalkanes in good agreement with the observed values. The atomic charges obtained by this scheme are compared with other estimates of these charges. They are similar to those derived from a simple LCAO–MO scheme but differ from those obtained by population analysis of more refined quantum mechanical calculations.

πŸ“œ SIMILAR VOLUMES

Approaches to charge calculations in mol
Approaches to charge calculations in molecular mechanics. 2 Resonance effects in conjugated systems
✍ Raymond J. Abraham; Brian Hudson πŸ“‚ Article πŸ“… 1984 πŸ› John Wiley and Sons 🌐 English βš– 859 KB

A previously published scheme of estimating atomic charges in haloalkanes is extended to include olefines, alcohols amines, acids, ethers, and amides. In the conjugated systems the effects of mesomeric transfer of charge are explicitly included. Generally good agreement with the observed dipole mome

Charge calculations in molecular mechani
Charge calculations in molecular mechanics. III: Amino acids and peptides
✍ Raymond J. Abraham; Brian Hudson πŸ“‚ Article πŸ“… 1985 πŸ› John Wiley and Sons 🌐 English βš– 782 KB

Atomic charges obtained with a previously published charge scheme are given for amino acids and peptides. In order to do this, a method of handling charged species with the basic has been developed. The charges obtained for alkylammonium ions and carboxylate ions with the scheme are presented and co