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

2008 ◽  
Vol 07 (01) ◽  
pp. 81-90
Author(s):  
SU-HONG GE ◽  
GUANG-XING DONG ◽  
XIN-LU CHENG ◽  
GUI-HUA SUN
Keyword(s):  
Density Functional Theory ◽  
Energy Transfer ◽  
Normal Mode ◽  
Transfer Rate ◽  
Density Functional ◽  
Molecular Size ◽  
Atomization Energy ◽  
Energy Transfer Rate ◽  
Functional Theory ◽  
Transfer Rates

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.

scholarly journals Hole Transfer in Open Carbynes

Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 3979
Author(s):  
Constantinos Simserides ◽  
Andreas Morphis ◽  
Konstantinos Lambropoulos
Keyword(s):  
Density Functional Theory ◽  
Ground State ◽  
Density Functional ◽  
State Energy ◽  
Frequency Content ◽  
Hydrogen Atoms ◽  
Functional Theory ◽  
Transfer Rates ◽  
Transfer Integrals ◽  
End Groups

We investigate hole transfer in open carbynes, i.e., carbon atomic nanowires, using Real-Time Time-Dependent Density Functional Theory (RT-TDDFT). The nanowire is made of N carbon atoms. We use the functional B3LYP and the basis sets 3-21G, 6-31G*, cc-pVDZ, cc-pVTZ, cc-pVQZ. We also utilize a few Tight-Binding (TB) wire models, a very simple model with all sites equivalent and transfer integrals given by the Harrison ppπ expression (TBI) as well as a model with modified initial and final sites (TBImod) to take into account the presence of one or two or three hydrogen atoms at the edge sites. To achieve similar site occupations in cumulenes with those obtained by converged RT-TDDFT, TBImod is sufficient. However, to achieve similar frequency content of charge and dipole moment oscillations and similar coherent transfer rates, the TBImod transfer integrals have to be multiplied by a factor of four (TBImodt4times). An explanation for this is given. Full geometry optimization at the B3LYP/6-31G* level of theory shows that in cumulenes bond length alternation (BLA) is not strictly zero and is not constant, although it is symmetrical relative to the molecule center. BLA in cumulenic cases is much smaller than in polyynic cases, so, although not strictly, the separation to cumulenes and polyynes, approximately, holds. Vibrational analysis confirms that for N even all cumulenes with coplanar methylene end groups are stable, for N odd all cumulenes with perpendicular methylene end groups are stable, and the number of hydrogen atoms at the end groups is clearly seen in all cumulenic and polyynic cases. We calculate and discuss the Density Functional Theory (DFT) ground state energy of neutral molecules, the CDFT (Constrained DFT) “ground state energy” of molecules with a hole at one end group, energy spectra, density of states, energy gap, charge and dipole moment oscillations, mean over time probabilities to find the hole at each site, coherent transfer rates, and frequency content, in general. We also compare RT-TDDFT with TB results.

Photophysical properties of acetylene-linked syn bimane oligomers: a molecular photonic wire

2018 ◽  
Vol 20 (2) ◽  
pp. 1150-1163
Author(s):  
T. S. Chwee ◽  
Z. C. Wong ◽  
M. B. Sullivan ◽  
W. Y. Fan
Keyword(s):  
Density Functional Theory ◽  
Wave Function ◽  
Energy Transfer ◽  
Excitation Energy ◽  
Density Functional ◽  
Photophysical Properties ◽  
Excitation Energy Transfer ◽  
Computational Studies ◽  
Functional Theory ◽  
Photonic Wire

Computational studies using correlated wave function methods and density functional theory were carried out on a series of acetylene-linked bimane oligomers with particular emphasis on their excitonic properties and implications for intra-chain excitation energy transfer (EET).

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