On the Possibility of Multi-Phonon Excitation of Internal Molecular Vibrations as the Rate Controlling Process in Shock Initiation

摘要

The possibility that the rate controlling process in shock-induced bond breaking in energetic materials is a transfer of lattice phonons to internal vibrations of the molecules of the explosive solid is examined. The rate at which three lattice phonons can excite an internal vibrational mode of the molecules of the lattice is estimated. This is then used to calculate the mean time for a molecule to be excited to a state having energy equal to the dissociation energy of the molecular bond, assuming no transfer of energy to other vibrational modes of the molecule and assuming a truncated harmonic oscillator form for the potential. It is noted that bonds that can not break at atmospheric pressure may be susceptible to unimolecular breaking at higher pressures, indicating that the reactions of slow thermal decomposition may not necessarily be the important reactions of shock induced bond breaking. (Author)