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Title: A theoretical study of the relaxation of a phenyl group chemisorbed to an RDX freestanding thin film

Abstract

Energy relaxation from an excited phenyl group chemisorbed to the surface of a crystalline thin film of α-1,3,5-trinitro-1,3,5-triazacyclohexane (α-RDX) at 298 K and 1 atm is simulated using molecular dynamics. Two schemes are used to excite the phenyl group. In the first scheme, the excitation energy is added instantaneously as kinetic energy by rescaling momenta of the 11 atoms in the phenyl group. In the second scheme, the phenyl group is equilibrated at a higher temperature in the presence of static RDX geometries representative of the 298 K thin film. An analytical model based on ballistic phonon transport that requires only the harmonic part of the total Hamiltonian and includes no adjustable parameters is shown to predict, essentially quantitatively, the short-time dynamics of the kinetic energy relaxation (∼200 fs). The dynamics of the phenyl group for times longer than about 6 ps follows exponential decay and agrees qualitatively with the dynamics described by a master equation. Long-time heat propagation within the bulk of the crystal film is consistent with the heat equation.

Authors:
;  [1]
  1. Department of Chemistry, University of Missouri-Columbia, Columbia, Missouri 65211-7600 (United States)
Publication Date:
OSTI Identifier:
22679029
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 145; Journal Issue: 5; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; CHEMISORPTION; CRYSTALS; EXCITATION; KINETIC ENERGY; MOLECULAR DYNAMICS METHOD; RELAXATION; TEMPERATURE RANGE 0400-1000 K; THIN FILMS

Citation Formats

Pereverzev, Andrey, E-mail: pereverzeva@missouri.edu, and Sewell, Thomas D., E-mail: sewellt@missouri.edu. A theoretical study of the relaxation of a phenyl group chemisorbed to an RDX freestanding thin film. United States: N. p., 2016. Web. doi:10.1063/1.4959281.
Pereverzev, Andrey, E-mail: pereverzeva@missouri.edu, & Sewell, Thomas D., E-mail: sewellt@missouri.edu. A theoretical study of the relaxation of a phenyl group chemisorbed to an RDX freestanding thin film. United States. doi:10.1063/1.4959281.
Pereverzev, Andrey, E-mail: pereverzeva@missouri.edu, and Sewell, Thomas D., E-mail: sewellt@missouri.edu. Sun . "A theoretical study of the relaxation of a phenyl group chemisorbed to an RDX freestanding thin film". United States. doi:10.1063/1.4959281.
@article{osti_22679029,
title = {A theoretical study of the relaxation of a phenyl group chemisorbed to an RDX freestanding thin film},
author = {Pereverzev, Andrey, E-mail: pereverzeva@missouri.edu and Sewell, Thomas D., E-mail: sewellt@missouri.edu},
abstractNote = {Energy relaxation from an excited phenyl group chemisorbed to the surface of a crystalline thin film of α-1,3,5-trinitro-1,3,5-triazacyclohexane (α-RDX) at 298 K and 1 atm is simulated using molecular dynamics. Two schemes are used to excite the phenyl group. In the first scheme, the excitation energy is added instantaneously as kinetic energy by rescaling momenta of the 11 atoms in the phenyl group. In the second scheme, the phenyl group is equilibrated at a higher temperature in the presence of static RDX geometries representative of the 298 K thin film. An analytical model based on ballistic phonon transport that requires only the harmonic part of the total Hamiltonian and includes no adjustable parameters is shown to predict, essentially quantitatively, the short-time dynamics of the kinetic energy relaxation (∼200 fs). The dynamics of the phenyl group for times longer than about 6 ps follows exponential decay and agrees qualitatively with the dynamics described by a master equation. Long-time heat propagation within the bulk of the crystal film is consistent with the heat equation.},
doi = {10.1063/1.4959281},
journal = {Journal of Chemical Physics},
number = 5,
volume = 145,
place = {United States},
year = {Sun Aug 07 00:00:00 EDT 2016},
month = {Sun Aug 07 00:00:00 EDT 2016}
}