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A noteworthy feature of bond dissociation/formation reactions
Author(s) -
Politzer Peter,
Murray Jane S.,
Lane Pat,
ToroLabbé Alejandro
Publication year - 2007
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.21400
Subject(s) - chemistry , dissociation (chemistry) , bond dissociation energy , sextuple bond , bond length , bond order , maxima and minima , bond energy , computational chemistry , crystallography , molecule , crystal structure , organic chemistry , mathematical analysis , mathematics
The reaction force F(R c ) of a process is the negative derivative of the potential energy V (R c ) of the system with respect to the intrinsic reaction coordinate R c . For the dissociation of a bond, F(R c ) has a negative minimum at a point R c = α, while for the formation of the same bond, F(R c ) has a maximum at R c = α. These extrema divide the respective processes into two phases. For the dissociation, these correspond to an initial stretching of the XY bond (structural effect) followed by separation into the fragments X and Y (electronic effects); for bond formation, the electronic phase is first (attractive interaction and gradual bond formation) and then the structural (relaxation to equilibrium separation). The noteworthy feature is that the key point R c = α always is such that V (α), relative to the minimum of V (R c ), is about 27% of the dissociation energy. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2007