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Electron distributions in radicals
Author(s) -
Staroverov Viktor N.,
Davidson Ernest R.
Publication year - 2000
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/(sici)1097-461x(2000)77:1<316::aid-qua30>3.0.co;2-5
Subject(s) - unpaired electron , singlet state , electron , spin (aerodynamics) , wave function , chemistry , eigenfunction , charge density , atomic physics , open shell , physics , molecular physics , quantum mechanics , excited state , thermodynamics , eigenvalues and eigenvectors
Properties and potential applications of novel electron distributions, such as the charge densities associated with singlet and triplet electron pairs, ρ 0 ( r ) and ρ 1 ( r ), and the distributions of “effectively unpaired” spin‐up and spin‐down electrons, Δ α ( r ) and Δ β ( r ), are discussed. Given the total spin S in an N ‐electron system described with a wave function which is a spin eigenfunction, ρ 0 ( r ) and ρ 1 ( r ) can be expressed as linear combinations of the charge and spin densities and are independent of the spin projection quantum number M . The proposed definition of the density of effectively unpaired electrons approaches the concept of electron pairing in a more general fashion than the traditional spin density. Distributions Δ α ( r ), Δ β ( r ), and their sum Δ( r ) are particularly suitable for open‐shell singlet states and diradicals and can be used to describe the variation of the radicaloid character of a molecule along a reaction path. The discussion is illustrated by calculations on selected singlet and triplet states of the methylene (CH 2 ) radical. © 2000 John Wiley & Sons, Inc. Int J Quant Chem 77: 316–323, 2000