DENSITY FUNCTIONAL THEORY STUDY OF THE ENERGY TRANSFER RATES, MOLECULAR SIZE, AND ATOMIZATION ENERGIES OF SOME SECONDARY EXPLOSIVE MOLECULES

Abstract

In this paper, we suggested a theoretical relationship between the property of molecular atomization energy and energy transfer rate in explosive detonation. According to the theory of Dlott and Fayer (J Chem Phys92(6):3798, 1990) some explosives are stable molecules with large energy barriers to chemical reaction in shock or impact initiation, so, a sizable amount of phonon energy must be converted to the molecular internal higher vibrations by multiphonon up pumping. To investigate the relationship between atomization energies and energy transfer rate, the number of doorway modes of explosives is estimated by their theory in which the rate is proportional to the number of normal mode vibrations. We evaluated frequencies of normal mode vibrations of TNB, TNAP, TNA, DATB, TATB, 2,4,6-trinitro-benzylalcohol ( C 7 H 5 N 3 O 7), and TNR by means of density functional theory (DFT) at the B3P86/6-31G(d, p) level. It is found that the number of doorway modes shows a linearly correlation to the atomization energies also calculated by means of DFT at the B3P86/6-31G(d, p) level. Besides, we studied the relation between the number of atoms and atomization energies for these molecules, and confirmed that for those secondary explosives molecules with similar molecular structure and similar molecular weight, the correlation between the atomization energy and the number of doorway modes is higher. This relationship is beneficial to the understanding of the property of explosive in detonation.