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Molecular Force Fields and Valency

  • J. W. Linnett

Abstract

The study of intramolecular force fields for small nuclear displacements provides a means of extending our knowledge and understanding of valency. For the chemist, the most useful expression for the force field is in terms of bond-length changes and bond-angle changes. The quadratic form for small displacements is then
$$ 2V = \sum\limits_i {{k_i}\Delta r_i^2 + \sum\limits_{ij} {{k_{ij}}\Delta r{}_i\Delta {r_j} + \sum\limits_p {{k_p}\Delta \alpha _p^2 + \sum\limits_{pq} {{k_{pq}}\Delta {\alpha _p}\Delta {\alpha _q} + \sum\limits_{ip} {{k_{ip}}\Delta {r_i}\Delta {\alpha _p}} } } } } $$
(1.1)
where the summation is over all bonds and all interbond angles; Δr i = r i - r ei , where r ei is the equilibrium length of the ith bond, and Δα p = α p - α ep , where α ep is the equilibrium value of the pth angle. There are two types of constants in equation (1.1): the main constants k i (bond) and k p (angle), and the interaction constants k ij (bond-bond), k pq (angle-angle) and k ip (bond-angle).

Keywords

Force Constant Interaction Constant Formal Charge Potential Energy Function Equilibrium Length 
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.

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Copyright information

© A. J. Downs, D. A. Long, L. A. K. Staveley 1971

Authors and Affiliations

  • J. W. Linnett

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