Ab initio calculations of the effects of H+ and NH4+ on the initial decomposition of HMX

Wang, Luoxin; Tuo, Xinlin; Yi, Changhai; Wang, Xiaogong

doi:10.1016/j.jmgm.2008.06.007

Cited by 10 publications

(4 citation statements)

References 29 publications

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“…Recently, the effect of defects and surface to initial reaction process of condensed phase HMX decomposition attracted more attention. ,,− Sharia and Kuklja , found the surface and vacancy caused a nonequilibrium vibration of N–NO 2 bond, which would decrease the potential barrier of homolytic cleavage of the N–NO 2 bond. Zhou and Huang suggested that molecular vacancies could help to decrease the activation energy barrier and increase the reaction rate.…”

Section: Introductionmentioning

confidence: 99%

Dynamic Responses and Initial Decomposition under Shock Loading: A DFTB Calculation Combined with MSST Method for β-HMX with Molecular Vacancy

Ji²,

Liu

et al. 2015

J. Phys. Chem. B

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Despite extensive efforts on studying the decomposition mechanism of HMX under extreme condition, an intrinsic understanding of mechanical and chemical response processes, inducing the initial chemical reaction, is not yet achieved. In this work, the microscopic dynamic response and initial decomposition of β-HMX with (1 0 0) surface and molecular vacancy under shock condition, were explored by means of the self-consistent-charge density-functional tight-binding method (SCC-DFTB) in conjunction with multiscale shock technique (MSST). The evolutions of various bond lengths and charge transfers were analyzed to explore and understand the initial reaction mechanism of HMX. Our results discovered that the C-N bond close to major axes had less compression sensitivity and higher stretch activity. The charge was transferred mainly from the N-NO2 group along the minor axes and H atom to C atom during the early compression process. The first reaction of HMX primarily initiated with the fission of the molecular ring at the site of the C-N bond close to major axes. Further breaking of the molecular ring enhanced intermolecular interactions and promoted the cleavage of C-H and N-NO2 bonds. More significantly, the dynamic response behavior clearly depended on the angle between chemical bond and shock direction.

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Section: Introductionmentioning

confidence: 99%

Dynamic Responses and Initial Decomposition under Shock Loading: A DFTB Calculation Combined with MSST Method for β-HMX with Molecular Vacancy

Ji²,

Liu

et al. 2015

J. Phys. Chem. B

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“…Density functional theory (DFT) has been utilized to study the energetic materials [17][18][19][20]. The calculations on azobenzene, whose structure is very similar to that of azofurazan, have shown that the hybrid B3LYP/6-31G* method can accurately reproduce the experimental geometries [21,22].…”

Section: Computational Detailsmentioning

confidence: 99%

Theoretical study on the trans–cis isomerization and initial decomposition of energetic azofurazan and azoxyfurazan

Wang

Tuo

et al. 2009

Journal of Molecular Graphics and Modelling

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“…Previous theoretical and experimental studies have shown that NO 2 fission (N-N bond fission or N-N bond dissociation), HONO elimination, concerted ring scission, and dissociation of the ring along the C–N bond are the possible initial unimolecular reaction mechanisms during the RDX and HMX decomposition process456. Among the listed reaction mechanisms, NO 2 fission is considered as the vital reaction, especially at higher temperatures7.…”

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confidence: 99%

Ab Initio Calculations of the N-N Bond Dissociation for the Gas-phase RDX and HMX

Liu

et al. 2017

Sci Rep

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NO2 fission is a vital factor for 1,3,5-Trinitroperhydro-1,3,5-triazine (RDX) and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) decomposition. In this study, the geometry of the gas-phase RDX and HMX molecules was optimized, and the bond order and the bond dissociation energy of the N-N bonds were examined. Moreover, the rate constants of the gas-phase RDX and HMX conformers, concerning the N-N bond dissociation, were evaluated using the microcanonical variational transition state theory (μVT). The calculation results have shown that HMX is more stable than RDX in terms of the N-N bond dissociation, and the conformers stability parameters were as follows: RDXaaa < RDXaae < HMX I < HMX II. In addition, for the RDX conformers, the N-N bond of the pseudo-equatorial positioning of the nitro group was more stable than the N-N bond of the axial positioning of the nitro group, while the results were opposite in the case of the HMX conformers. Moreover, it has been shown that the dissociation rate constant of the N-N bond is influenced by the temperature significantly, thus the rate constants were much lower (<10−10 s−1) when the temperature was less than 1000 K.

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Ab initio calculations of the effects of H+ and NH4+ on the initial decomposition of HMX

Cited by 10 publications

References 29 publications

Dynamic Responses and Initial Decomposition under Shock Loading: A DFTB Calculation Combined with MSST Method for β-HMX with Molecular Vacancy

Dynamic Responses and Initial Decomposition under Shock Loading: A DFTB Calculation Combined with MSST Method for β-HMX with Molecular Vacancy

Theoretical study on the trans–cis isomerization and initial decomposition of energetic azofurazan and azoxyfurazan

Ab Initio Calculations of the N-N Bond Dissociation for the Gas-phase RDX and HMX

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