Accession Number : ADA132236

Title :   Shock Induced Molecular Excitation in Solids.

Descriptive Note : Interim rept.,


Personal Author(s) : Zerilli,Frank J

PDF Url : ADA132236

Report Date : 06 Apr 1983

Pagination or Media Count : 63

Abstract : Initiation of condensed explosives is studied on a molecular level with a quantum mechanical calculation of transition rates for shock induced transitions between low lying internal molecular normal mode states in a molecular solid. It is assumed that the shock produces a distribution of acoustic phonons which becomes thermalized before any significant internal mode phonons are created. The calculation uses the Born-Oppenheimer approximation in which the internal modes constitute the fast subsystem and the acoustic modes constitute the slow system. A sample calculation is done for nitromethane. Generally speaking, the lowest frequency internal modes have the fastest shock induced transition rates, with the transition from the ground to first excited state being the slowest. The transition rates increase by six to ten orders of magnitude from the values under normal conditions when nitromethane is subjected to shocks of 50 to 300 kbar. The transition lifetimes are compared with, and show some correlation with, the pressure-time critical shock initiation data obtained by de Longueville, Fauquignon, and Moulard.

Descriptors :   *Shock waves, *Excitation, *Molecules, *Solids, Energy transfer, Nitromethane, Adiabatic conditions, Interactions, Phonons, Acoustics, Computations, Distribution, Excitation, Explosives, Internal, Life expectancy(Service Life), Molecular states, Molecules, Nitromethane, Normality, Phonons, Quantum theory, Rates, Shock, Solids, Transitions

Subject Categories : Ammunition and Explosives
      Atomic and Molecular Physics and Spectroscopy
      Nuclear Physics & Elementary Particle Physics

Distribution Statement : APPROVED FOR PUBLIC RELEASE