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Analysis of diatomic bond dissociation and formation in terms of the reaction force and the position-dependent reaction force constant

Murray JS, Toro-Labbe A, Clark T, Politzer P (2009)

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Publication Status: Published

Publication Type: Journal article

Publication year: 2009

Journal

Publisher: Springer Verlag (Germany)

Book Volume: 15

Pages Range: 701-706

Journal Issue: 6

DOI: 10.1007/s00894-008-0400-2

Abstract

Bond dissociation and formation in diatomic molecules are analyzed in terms of the reaction force F(R) and the reaction force constant kappa(R). These were determined for a group of 13 molecules from their extended-Rydberg potential energy functions V(R), which are of near-experimental quality. From F(R) and kappa(R) comes a two-stage description of dissociation/formation. In dissociation, the first stage involves stretching of the bond, which is opposed by an increasingly negative retarding force F(R). This reaches a minimum and then begins to weaken in the second stage, which is the transition from stretched molecule to free atoms. Bond formation begins with the reverse transition, driven by a positive F(R) which reaches a maximum for the stretched molecule and then becomes a decreasing restoring force. In the stages in which the system is a stretched molecule, kappa(R) is positive with its maximum at the equilibrium bond length; it is zero at the minimum or maximum of F(R), and negative throughout the transition stages, going through a minimum. kappa(R) < 0 has been found to characterize the transition portion of a reaction. This description of dissociation/formation is reinforced by computed B3LYP and Hartree-Fock force constants at different atom separations for the singlet molecules. Hartree-Fock wave function stability assessments suggest that, for the single-bonded singlet molecules, the onset of electron unpairing in dissociation comes in the neighborhood of the F(R) minimum.

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APA:

Murray, J.S., Toro-Labbe, A., Clark, T., & Politzer, P. (2009). Analysis of diatomic bond dissociation and formation in terms of the reaction force and the position-dependent reaction force constant. Journal of Molecular Modeling, 15(6), 701-706. https://dx.doi.org/10.1007/s00894-008-0400-2

MLA:

Murray, Jane S., et al. "Analysis of diatomic bond dissociation and formation in terms of the reaction force and the position-dependent reaction force constant." Journal of Molecular Modeling 15.6 (2009): 701-706.

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