Su-hong Ge

Reaction of H2 and N+ Ion under Titan's Atmosphere

Abstract The thermochemical properties of reaction N + +H 2 →NH + +H have been computed under Titans atmosphere conditions. It is observed that this reaction is an endothermic reaction and cannot proceed forward spontaneously under low temperature. The rate for this reaction at 300 K has been calculated as k =4.16×10 −10 cm 3 ·mol −1 ·s −1 . The reaction barrier is 109.847 kJ·mol −1 at 298.15 K, which is probably too high to allow this reaction to occur in the atmosphere of Titan. The kinetic properties of the reaction are calculated at a pressure of 90 Pa and a temperature ranging from 1 to 5000 K. It is found that this reaction has a very low reaction rate under low temperature in Titans atmosphere and that the rate decreases drastically with decreasing temperature. This result should be applicable to interstellar place with low temperature values. The results are compared with those obtained from experiments.

Correlation Between Energy Transfer Rate and Atomization Energy of Some Trinitro Aromatic Explosive Molecules

An assumptive theoretical relationship is suggested to describe the property of molecular atomization energy and energy transfer rate in the initiation of explosions. To investigate the relationship between atomization energy and energy transfer rate, the number of doorway modes of explosives is estimated by the theory of Dlott and Fayer in which the rate is proportional to the number of normal mode vibrations. It was evaluated frequencies of normal mode vibrations of eight molecules 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 linear correlation to the atomization energies of the molecules, which were also calculated by means of the same method. A mechanism of this correlation is discussed. It is also noted that in those explosives with similar molecular structure and molecular weight, the correlation between the atomization energy and the number of doorway modes is higher.

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

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 (C7H5N3O7), 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.

STRUCTURAL AND ELECTRONIC PROPERTIES OF Sr(N3)2 UNDER PRESSURE

Structural and electronic properties of Sr(N3)2 under pressure up to 120 GPa are studied by means of SIESTA calculation. The pressure–angle as well as the cell parameters relation respect to pressure is employed to study the structural changes under pressure. The obtained N–N bond length at zero pressure is in agreement with the other works. The energy band gap takes on the trend of decreasing below 20 GPa and this trend could result in the reduction of the stability for Sr(N3)2 crystal, but at 30 GPa it increases suddenly. And polymorphic transformation is observed. The ionic configuration for Sr(N3)2 in the fundamental state is estimated to be Sr+1.200N-0.200. The charge density of N atom is more sensitive to pressure variation than that of Sr atom.