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Author Pereverzev, Andrey ♦ Sewell, Thomas D.
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY ♦ CHEMISORPTION ♦ CRYSTALS ♦ EXCITATION ♦ KINETIC ENERGY ♦ MOLECULAR DYNAMICS METHOD ♦ RELAXATION ♦ TEMPERATURE RANGE 0400-1000 K ♦ THIN FILMS
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.
ISSN 00219606
Educational Use Research
Learning Resource Type Article
Publisher Date 2016-08-07
Publisher Place United States
Journal Journal of Chemical Physics
Volume Number 145
Issue Number 5


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