The mechanochemical effects of 5 nm spherical heterogeneities on the reactivity of shocked crysta... more The mechanochemical effects of 5 nm spherical heterogeneities on the reactivity of shocked crystalline erythritol tetranitrate (ETN), an emerging improvised explosive, are revealed for the first time. Reactive molecular dynamics simulations in conjunction with the symmetric plate-impact technique, are employed to characterize different stages of the process, including shock–void interaction, void collapse, enhanced reactivity, and subsequent molecular decomposition. The formation of supersonic nanojets from the proximal void surface is observed to greatly enhance local heating following impact of the nanojets on the distant void surface. It is demonstrated that the nanovoid collapse closely matches a Rayleigh-type hydrodynamic bubble collapse, including a spherical-to-crescent shape transformation. The chemical decomposition mechanism of condensed phase ETN is analyzed and is shown to follow a unimolecular path. The molecular decomposition of a defect containing crystal occurs with significantly higher ra...
The structure of a thermodynamically consistent master equation for a driven system is obtained b... more The structure of a thermodynamically consistent master equation for a driven system is obtained by imposing a set of thermodynamic postulates. The analysis is based on a time-independent autonomous construction, incorporating the drive as a large transient control quantum system. Under these assumptions, by partitioning the control and primary system we derive the semi-classical description. In this framework, the drive is incorporated as a time-dependent term in the primary system Hamiltonian. The resulting structure of the master equation is determined by a set of eigenoperators of the driven free dynamics. We demonstrate the theory by analyzing a qubit controlled by a single bosonic mode in a coherent state.
The Carnot cycle combines reversible isothermal and adiabatic strokes to obtain optimal efficienc... more The Carnot cycle combines reversible isothermal and adiabatic strokes to obtain optimal efficiency, at the expense of a vanishing power output. Quantum Carnot-analog cycles are constructed and solved, operating irreversibly with positive power. Swift thermalization is obtained in the isotherms utilizing shortcut to equilibrium protocols and the adiabats employ frictionless unitary shortcuts. The working medium in this study is composed of a particle in a driven harmonic trap. For this system, we solve the dynamics employing a generalized canonical state. Such a description incorporates both changes in energy and coherence. This allows comparing three types of Carnot-analog cycles, Carnot-shortcut, Endo-shortcut and Endo-global. The Carnot-shortcut engine demonstrates the trade-off between power and efficiency. It posses a maximum in power, a minimum cycle-time where it becomes a dissipator and for a diverging cycle-time approaches the ideal Carnot efficiency. The irreversibility of ...
Berichte der Bunsengesellschaft für physikalische Chemie, 1985
Mode specific resonance decay is demonstrated directly by Fast Fourier Transform (FFT) time propa... more Mode specific resonance decay is demonstrated directly by Fast Fourier Transform (FFT) time propagation of resonance wave packets for an ABA molecule modeled by coupled Morse oscillators. Fast and slow decay correlates with local and hyperspherical modes which have their wave function lobes directed towards dissociation exits and ridges of the potential, respectively, in excellent analogy to Hose and Taylor's analysis of the Hénon‐Heiles system. The decay shows no correlation with energy or symmetry. The FFT method yields details of the decay mechanism. The results are related to observations of mode specific unimolecular processes in bulk.
The mechanochemical effects of 5 nm spherical heterogeneities on the reactivity of shocked crysta... more The mechanochemical effects of 5 nm spherical heterogeneities on the reactivity of shocked crystalline erythritol tetranitrate (ETN), an emerging improvised explosive, are revealed for the first time. Reactive molecular dynamics simulations in conjunction with the symmetric plate-impact technique, are employed to characterize different stages of the process, including shock–void interaction, void collapse, enhanced reactivity, and subsequent molecular decomposition. The formation of supersonic nanojets from the proximal void surface is observed to greatly enhance local heating following impact of the nanojets on the distant void surface. It is demonstrated that the nanovoid collapse closely matches a Rayleigh-type hydrodynamic bubble collapse, including a spherical-to-crescent shape transformation. The chemical decomposition mechanism of condensed phase ETN is analyzed and is shown to follow a unimolecular path. The molecular decomposition of a defect containing crystal occurs with significantly higher ra...
The structure of a thermodynamically consistent master equation for a driven system is obtained b... more The structure of a thermodynamically consistent master equation for a driven system is obtained by imposing a set of thermodynamic postulates. The analysis is based on a time-independent autonomous construction, incorporating the drive as a large transient control quantum system. Under these assumptions, by partitioning the control and primary system we derive the semi-classical description. In this framework, the drive is incorporated as a time-dependent term in the primary system Hamiltonian. The resulting structure of the master equation is determined by a set of eigenoperators of the driven free dynamics. We demonstrate the theory by analyzing a qubit controlled by a single bosonic mode in a coherent state.
The Carnot cycle combines reversible isothermal and adiabatic strokes to obtain optimal efficienc... more The Carnot cycle combines reversible isothermal and adiabatic strokes to obtain optimal efficiency, at the expense of a vanishing power output. Quantum Carnot-analog cycles are constructed and solved, operating irreversibly with positive power. Swift thermalization is obtained in the isotherms utilizing shortcut to equilibrium protocols and the adiabats employ frictionless unitary shortcuts. The working medium in this study is composed of a particle in a driven harmonic trap. For this system, we solve the dynamics employing a generalized canonical state. Such a description incorporates both changes in energy and coherence. This allows comparing three types of Carnot-analog cycles, Carnot-shortcut, Endo-shortcut and Endo-global. The Carnot-shortcut engine demonstrates the trade-off between power and efficiency. It posses a maximum in power, a minimum cycle-time where it becomes a dissipator and for a diverging cycle-time approaches the ideal Carnot efficiency. The irreversibility of ...
Berichte der Bunsengesellschaft für physikalische Chemie, 1985
Mode specific resonance decay is demonstrated directly by Fast Fourier Transform (FFT) time propa... more Mode specific resonance decay is demonstrated directly by Fast Fourier Transform (FFT) time propagation of resonance wave packets for an ABA molecule modeled by coupled Morse oscillators. Fast and slow decay correlates with local and hyperspherical modes which have their wave function lobes directed towards dissociation exits and ridges of the potential, respectively, in excellent analogy to Hose and Taylor's analysis of the Hénon‐Heiles system. The decay shows no correlation with energy or symmetry. The FFT method yields details of the decay mechanism. The results are related to observations of mode specific unimolecular processes in bulk.
Uploads