Electronic and ionization spectra of 1,1-diamino-2,2-dinitroethylene, FOX-7

Borges, Itamar

doi:10.1007/s00894-014-2095-x

Cited by 9 publications

(8 citation statements)

References 46 publications

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“…Our efforts on this subject have been inspired especially by the aforementioned works of Politzer, Murray, and Rice. In another direction in the search of greater understanding of energetic molecules, electronic excited states have also been investigated …”

Section: Introductionmentioning

confidence: 99%

“…In another direction in the search of greater understanding of energetic molecules, electronic excited states have also been investigated. [41][42][43][44][45] Regarding structural factors of the molecules, Mathieu observed that there is a relationship between the sensitivity of nitramines and their energy of dissociation and molecular energy per atom. [16] Politzer and Murray also established quantitative relationships between their sensitivities and some characteristics of the molecular surface electrostatic potentials that reflect the dominant positive central regions, a distinct property of an energetic molecule in contrast with a typical organic molecule.…”

Section: Introductionmentioning

confidence: 99%

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On the molecular origin of the sensitivity to impact of cyclic nitramines

Oliveira

Borges

2018

Int J of Quantum Chemistry

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Nitramine explosives can combine relative insensitivity to initiation and great energy content. In this work, based on a previous approach developed for nitroaromatic explosives, we propose four mathematical models to correlate impact sensitivity, given by the h50 value, to molecular charge properties. Fourteen cyclic nitramines were studied using Density Functional Theory (DFT). Six molecules of the set have measured h50 values, which were used to evaluate the sensitivity models. Converged DFT charge densities of the molecules were partitioned and analyzed according to the distributed multipole analysis (DMA) atom‐centered method. The sensitivity models were based on the DMA electric multipole values. The electron withdrawing role of the nitro group and the strong polarization of the charges of the nitrogen atom in the amine group were clearly identified. The influence of the electronic properties on the sensitivity of the explosives was characterized by including in the sensitivity models the charge values of the nitro or the nitramine groups and electron delocalization, the latter quantified by the DMA quadrupole values of the ring atoms. Inclusion of electron delocalization effects can improve the prediction of h50 values for two out of the five strained‐ring nitramines in the set. The charge values of the nitramine groups are the most important molecular property affecting the impact sensitivity. The h50 values of eight nitramine explosives of the set not available experimentally were computed.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

On the molecular origin of the sensitivity to impact of cyclic nitramines

Oliveira

Borges

2018

Int J of Quantum Chemistry

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“…We investigated previously using high-level ab initio wave functions gas-phase electronic excitation spectra of nitro molecules component of representative energetic materials, namely, nitramide, H 2 NNO 2 , [23] N,N-dimethylnitramine, (CH 3 ) 2 NNO 2 , [15] hexahydro-1,3,5-trinitro-1,3,5-triazine, known as RDX, [24] nitroethylene, H 2 C@CHNO 2 , [21,25] and 1,1-diamino-2,2-dinitroethylene, FOX-7. [26] These molecules have XANO 2 bonds (X 5 N,C) usually present in widely used energetic materials. [27] The very weakly bonded NO 2 group in these molecules is easily withdrawn.…”

Section: Introductionmentioning

confidence: 99%

“…Nitro compounds are usually thermally unstable and composed of easily broken covalent bonds such as NN, OC, and CN. We investigated previously using high‐level ab initio wave functions gas‐phase electronic excitation spectra of nitro molecules component of representative energetic materials, namely, nitramide, H 2 NNO 2 , N , N ‐dimethylnitramine, (CH 3 ) 2 NNO 2 , hexahydro‐1,3,5‐trinitro‐1,3,5‐triazine, known as RDX, nitroethylene, H 2 CCHNO 2 , and 1,1‐diamino‐2,2‐dinitroethylene, FOX‐7 . These molecules have XNO 2 bonds (X = N,C) usually present in widely used energetic materials .…”

Section: Introductionmentioning

confidence: 99%

Water solvent effects using continuum and discrete models: The nitromethane molecule, CH₃NO₂

2015

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The first three valence transitions of the two nitromethane conformers (CH3NO2) are two dark n → π* transitions and a very intense π → π* transition. In this work, these transitions in gas-phase and solvated in water of both conformers were investigated theoretically. The polarizable continuum model (PCM), two conductor-like screening (COSMO) models, and the discrete sequential quantum mechanics/molecular mechanics (S-QM/MM) method were used to describe the solvation effect on the electronic spectra. Time dependent density functional theory (TDDFT), configuration interaction including all single substitutions and perturbed double excitations (CIS(D)), the symmetry-adapted-cluster CI (SAC-CI), the multistate complete active space second order perturbation theory (CASPT2), and the algebraic-diagrammatic construction (ADC(2)) electronic structure methods were used. Gas-phase CASPT2, SAC-CI, and ADC(2) results are in very good agreement with published experimental and theoretical spectra. Among the continuum models, PCM combined either with CASPT2, SAC-CI, or B3LYP provided good agreement with available experimental data. COSMO combined with ADC(2) described the overall trends of the transition energy shifts. The effect of increasing the number of explicit water molecules in the S-QM/MM approach was discussed and the formation of hydrogen bonds was clearly established. By including explicitly 24 water molecules corresponding to the complete first solvation shell in the S-QM/MM approach, the ADC(2) method gives more accurate results as compared to the TDDFT approach and with similar computational demands. The ADC(2) with S-QM/MM model is, therefore, the best compromise for accurate solvent calculations in a polar environment.

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“…However, detailed information about the initial step and sustaining decomposition procedure of FOX‐7 including the formation process of some key intermediates and gas products in the vicinity of decomposition temperature is still unclear due to the complexity of decomposition reactions and difficulty in experimental handling. Theoretical methods such as energy minimization calculations 11–14 and dynamic simulations 15–17 provide us a better understanding of the decomposition behavior for FOX‐7 and can gain an insight into the decomposition reactions and processes easily and directly compared with experimental studies. Among these studies, the investigated temperatures 15 vary either around the room temperature or very high (i.e., 2,500–4,000 K), which are distinctively different from the temperatures of storing and using circumstances of FOX‐7 (500–1,000 K).…”

Section: Introductionmentioning

confidence: 99%

Coupling effects of high temperature and pressure on the decomposition mechanisms of 1,1‐diamino‐2,2‐dinitroehethe crystal: Ab initio molecular dynamics simulations

Xiong

Zhu

2020

J Chinese Chemical Soc

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Recently, Dreger et al. experimentally investigated the phase diagram and decomposition of 1,1-diamino-2,2-dinitroethene (FOX-7) single crystal compressed hydrostatically up to 10 GPa and heated over a range of 293-750 K (J. Phys. Chem. C 2016, 120, 11092-11098). As a continuation, we performed ab initio molecular dynamic simulations to study the initiation mechanisms and subsequent decomposition of FOX-7 at a temperature of 504 K (initial decomposition temperature) coupled with a pressure of 1-5 GPa, 604 K at 5GPa, and 704 K at 5 GPa. However, our two compressing ways are different: the former is static hydrostatical compression, while our way is dynamic compression. Our results indicate that the initial decomposition mechanism was dependent on the temperature but independent of the pressure. The initial decomposition step is the bimolecular intermolecular hydrogen transfer. The subsequent decomposition of FOX-7 is sensitive to both the temperature and pressure. At 504 K, the decomposition of FOX-7 was accelerated from 1 to 2 GPa and from 3 to 5 GPa but decelerated from 2 to 3 GPa. The temperature exhibits a positive effect on the decomposition. Overall, the temperature and pressure have great cooperative effects on the decomposition of FOX-7. Our study may provide new insight into understanding the initial mechanisms and decomposition reactions of energetic materials at relatively low temperatures coupled with different pressures in atomic detail. K E Y W O R D S ab initio molecular dynamics, FOX-7 crystal, initial decomposition, high temperatures and high pressures

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Electronic and ionization spectra of 1,1-diamino-2,2-dinitroethylene, FOX-7

Cited by 9 publications

References 46 publications

On the molecular origin of the sensitivity to impact of cyclic nitramines

On the molecular origin of the sensitivity to impact of cyclic nitramines

Water solvent effects using continuum and discrete models: The nitromethane molecule, CH₃NO₂

Coupling effects of high temperature and pressure on the decomposition mechanisms of 1,1‐diamino‐2,2‐dinitroehethe crystal: Ab initio molecular dynamics simulations

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Electronic and ionization spectra of 1,1-diamino-2,2-dinitroethylene, FOX-7

Cited by 9 publications

References 46 publications

On the molecular origin of the sensitivity to impact of cyclic nitramines

On the molecular origin of the sensitivity to impact of cyclic nitramines

Water solvent effects using continuum and discrete models: The nitromethane molecule, CH3NO2

Coupling effects of high temperature and pressure on the decomposition mechanisms of 1,1‐diamino‐2,2‐dinitroehethe crystal: Ab initio molecular dynamics simulations

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Water solvent effects using continuum and discrete models: The nitromethane molecule, CH₃NO₂