Molecular-dynamics study of detonation. II. The reaction mechanism

Rice, Betsy M.; Mattson, William D.; Grosh, John; Treviño, S. F.

doi:10.1103/physreve.53.623

Cited by 19 publications

(20 citation statements)

References 26 publications

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“…At the CJ state density, this repulsion breaks down and clusters of particles form. Similar behavior has also been observed in the systems that Rice et al studied ͓18,19͔ and in the snapshots reported by Brenner et al ͓16͔. To examine this behavior more closely, we examine the RDFs along the Hugoniot. In particular, we consider the case of Q = 1.5 eV, which has a convex section indicative of a phase transition.…”

Section: Cj Interpolationsupporting

confidence: 78%

Influence of interatomic bonding potentials on detonation properties

et al. 2007

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The dependences of the macroscopic detonation properties of a two-dimensional (2D) diatomic (AB) molecular system on the fundamental molecular properties were investigated. This includes examining the detonation velocity, reaction zone thickness, and critical width as functions of the exothermicity (Q) of the gas-phase reaction [AB --> (1/2)(A(2) + B(2))] and the gas-phase dissociation energy (D(e)(AB)) for AB --> A + B . Following previous work, molecular dynamics (MD) simulations with a reactive empirical bond-order potential were used to characterize the shock-induced response of a diatomic AB molecular solid, which exothermically reacts to produce A2 and B2 gaseous products. Nonequilibrium MD simulations reveal that there is a linear dependence between the square of the detonation velocity and both of these molecular parameters. The detonation velocities were shown to be consistent with the Chapman-Jouguet (CJ) model, demonstrating that these dependences arise from how the equation of state of the products and reactants are affected. Equilibrium MD simulations of microcanonical ensembles were used to determine the CJ states for varying Q 's, and radial distribution functions characterize the atomic structure. The character of this material near the CJ conditions was found to be somewhat unusual, consisting of polyatomic clusters rather than discrete molecular species. It was also found that there was a minimum value of Q and a maximum value of (D(e)(AB)) for which a pseudo-one-dimensional detonation could not be sustained. The reaction zone of this material was characterized under both equilibrium (CJ) and transient (underdriven) conditions. The basic structure is consistent with the Zeldovich-von Neumann-Döring model, with a sharp shock rise and a reaction zone that extends to 200-300 Angstrom. The underdriven systems show a buildup process which requires an extensive time to approach equilibrium conditions. The rate stick failure diameter (critical width in 2D) was also found to depend on Q and (D(e)(AB)). The dependence on Q could be explained in terms of the reaction zone properties.

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Section: Cj Interpolationsupporting

confidence: 78%

Influence of interatomic bonding potentials on detonation properties

et al. 2007

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“…The computation of forces scales linearly with the number of atoms, N, since there are no long-range interactions. Recently, only twodimensional (2D) simulations have been available for studies such as detonation instability [3][4][5][6][7][8] and hot-spot mediated detonation [9]. Threedimensional (3D) simulations are more desirable since the heat capacity is larger and richer physics can be expected, but these require vastly more computing power.…”

Section: Introductionmentioning

confidence: 99%

Molecular dynamics simulations of detonation on the roadrunner supercomputer

Mniszewski¹,

Cawkwell²,

Germann³

2012

AIP Conference Proceedings

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The temporal and spatial scales intrinsic to a real detonating explosive are extremely difficult to capture using molecular dynamics (MD) simulations. Nevertheless, MD remains very attractive since it allows for the resolution of dynamic phenomena at the atomic scale. Large-scale reactive MD simulations in three dimensions require immense computational resources even when simple reactive force fields are employed. We focus on the REBO force field for 'AB' since it has been shown to support a detonation while being simple, analytic, and short-ranged. The transition from two-to three-dimensional simulations is being facilitated by the port of the REBO force field in the parallel MD code SPaSM to LANL's petaflop supercomputer 'Roadrunner'. We provide a detailed discussion of the challenges associated with computing interatomic forces on a hybrid Opteron/Cell BE computational architecture.

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“…[18][19][20][21][22][23] These rely on interatomic potentials capable of describing bond breaking and formation 19,[23][24][25] necessary to reproduce chemical reactions leading to detonation. Such potentials are, however, developed to reproduce the electronic potential energy surface ͑PES͒ in the vicinity of equilibrium and transition structures.…”

Section: Introductionmentioning

confidence: 99%

Electronic structure and molecular dynamics of breaking the RO–NO2 bond

Schweigert

Dunlap

2009

The Journal of Chemical Physics

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Decomposition of energetic molecules such as pentaerythritol tetranitrate is accompanied by extensive changes in their electronic configuration and thus is challenging for ab initio Born-Oppenheimer molecular dynamics simulations. The performance of single-determinant methods (in particular, density-functional theory) is validated on electronic structure and molecular dynamics simulations of RO-NO(2) bond dissociation in a smaller nitric ester, ethyl nitrate. Accurate description of dissociating molecule requires using unrestricted, spin-symmetry-broken orbitals. However, the iterative self-consistent field procedure is prone to convergence failures in the bond-breaking region even if robust convergence algorithms are employed. As a result, molecular dynamics simulations of unimolecular decomposition need to be closely monitored and manually restarted to ensure seamless transition from the closed-shell to open-shell configuration.

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Molecular-dynamics study of detonation. II. The reaction mechanism

Cited by 19 publications

References 26 publications

Influence of interatomic bonding potentials on detonation properties

Influence of interatomic bonding potentials on detonation properties

Molecular dynamics simulations of detonation on the roadrunner supercomputer

Electronic structure and molecular dynamics of breaking the RO–NO2 bond

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