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Quantum Mechanics and Molecular Dynamics Calculations provide new evidence for a free‐radical shock initiation model
Author(s) -
Walker F. E.
Publication year - 1982
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.19820070103
Subject(s) - detonation , explosive material , shock (circulatory) , shock wave , covalent bond , molecular dynamics , chemical physics , acceleration , mechanics , physics , materials science , chemistry , classical mechanics , computational chemistry , quantum mechanics , medicine , organic chemistry
Abstract The contrast between a hydrodynamic model for shock initiation of explosives and a newer microscopic free‐radical model is presented. The primary considerations of the free‐radical model are that shock energy is very coherent and that it is strong enough to cause mechanical fracture of covalent bonds. The shock front on a microscopic scale is very narrow (∼5 Å to 15 Å) and thermal equilibrium does not exist in the front. The free atoms and radicals formed by the shear and acceleration forces in the shock front initiate the chemical reaction that leads to hot spots and the eventual decomposition of the explosive materials. Energy‐release rates and vibrational velocities of the covalently bound atoms are factors in establishing detonation velocities. A number of explosives phenomena are discussed as the new model provides explanations for them. New information from molecular dynamics and quantum mechanical calculations on shock waves in condensed systems and recent experimental data are shown to support the free‐radical model.