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Energy‐based formalism for the mapping analysis of concerted reactions
Author(s) -
Trindle Carl,
Collins Francis S.
Publication year - 2009
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.560050721
Subject(s) - antibonding molecular orbital , formalism (music) , excited state , wave function , potential energy , chemistry , theoretical physics , computational chemistry , physics , quantum mechanics , electron , art , musical , atomic orbital , visual arts
A multiconfigurational mapping formalism is developed, by which the states of a set of reaction products are described in terms of the configurations of the original reactant system. Each reactant configuration is mapped into a wave function of the products, and an optimum mix of the mapped functions is obtained by configuration interaction. The principle governing the mapping is that the topology of bonding and antibonding in the system cannot be altered, although the shapes of the bonding and antibonding regions can be distorted by bends, twists, and stretches. Results of the calculation allow predictions of allowed or forbidden nature of reactions similar to those of Woodward and Hoffmann [1], but the new analysis is fully automated and independent of point group symmetry. Identification of the particular excited state(s) leading to certain products in thermally forbidden reactions is considerably simplified by this analysis. Calculations on relatively well‐understood systems, the pyrolysis of cyclobutane and the closure of both a symmetric and chiral butadiene, illustrate this approach to the study of concerted reactions.