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Charge Density Distribution, Electrostatic Properties, and Impact Sensitivity of the High Energetic Molecule TNB: A Theoretical Charge Density Study
Author(s) -
Stephen Arputharaj David,
Kumaradhas Poomani,
Pawar Rajesh B.
Publication year - 2011
Publication title -
propellants, explosives, pyrotechnics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.56
H-Index - 65
eISSN - 1521-4087
pISSN - 0721-3115
DOI - 10.1002/prep.201000073
Subject(s) - molecule , charge density , electron density , bond energy , bond order , covalent bond , bent bond , chemical bond , chemistry , charge (physics) , atoms in molecules , single bond , sextuple bond , chemical physics , bond strength , electron localization function , computational chemistry , bond length , electron , physics , group (periodic table) , organic chemistry , quantum mechanics , adhesive , layer (electronics)
A quantum chemical calculation and a charge density analysis have been performed on the energetic molecule trinitrobenzene (TNB) to characterize its bond strength and to relate the bond topological parameters with the impact sensitivity. The optimized geometry of the molecule was calculated by the density functional method B3P86 with the basis set 6‐311G**. The bond topological analysis predicts a significantly low bond electron density (∼1770 e nm −3 ) as well as Laplacian of electron density (−1.67×10 6 e nm −5 ) for CN bonds. This low value of the Laplacian indicates, the charges of these bonds are highly depleted, which confirms that these are the weakest bonds in the molecule. The N=O bonds bear a high negative value of Laplacian, reflecting that the bond charges are highly concentrated. The isosurface of the molecular, electrostatic potential (ESP) shows large electronegative regions at the vicinity of NO 2 groups. Further analysis of ESP in the bonding region allows predicting the impact sensitivity. A sound relationship has been found between the ESP at the mid point of the bonds and its bond charge depletion. The positive ESP at the mid points of highly charge depleted CNO 2 bonds reveals that these bonds are the sensitive bonds in the molecule.