skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Pressure effects on the relaxation of an excited nitromethane molecule in an argon bath

Abstract

Classical molecular dynamics simulations were performed to study the relaxation of nitromethane in an Ar bath (of 1000 atoms) at 300 K and pressures 10, 50, 75, 100, 125, 150, 300, and 400 atm. The molecule was instantaneously excited by statistically distributing 50 kcal/mol among the internal degrees of freedom. At each pressure, 1000 trajectories were integrated for 1000 ps, except for 10 atm, for which the integration time was 5000 ps. The computed ensemble-averaged rotational energy decay is similar to 100 times faster than the vibrational energy decay. Both rotational and vibrational decay curves can be satisfactorily fit with the Lendvay-Schatz function, which involves two parameters: one for the initial rate and one for the curvature of the decay curve. The decay curves for all pressures exhibit positive curvature implying the rate slows as the molecule loses energy. The initial rotational relaxation rate is directly proportional to density over the interval of simulated densities, but the initial vibrational relaxation rate decreases with increasing density relative to the extrapolation of the limiting low-pressure proportionality to density. The initial vibrational relaxation rate and curvature are fit as functions of density. For the initial vibrational relaxation rate, the functional form of themore » fit arises from a combinatorial model for the frequency of nitromethane "simultaneously" colliding with multiple Ar atoms. Roll-off of the initial rate from its low-density extrapolation occurs because the cross section for collision events with L Ar atoms increases with L more slowly than L times the cross section for collision events with one Ar atom. The resulting density-dependent functions of the initial rate and curvature represent, reasonably well, all the vibrational decay curves except at the lowest density for which the functions overestimate the rate of decay. The decay over all gas phase densities is predicted by extrapolating the fits to condensed-phase densities. (C) 2015 AIP Publishing LLC.« less

Authors:
; ORCiD logo; ;
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); U.S. Army Research Laboratory - U.S. Army Research Office (ARO)
OSTI Identifier:
1393974
DOE Contract Number:  
AC02-06CH11357
Resource Type:
Journal Article
Journal Name:
Journal of Chemical Physics
Additional Journal Information:
Journal Volume: 142; Journal Issue: 1; Journal ID: ISSN 0021-9606
Publisher:
American Institute of Physics (AIP)
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS; classical trajectory; energy relaxation; high pressure; nitromethane

Citation Formats

Rivera-Rivera, Luis A., Wagner, Albert F., Sewell, Thomas D., and Thompson, Donald L. Pressure effects on the relaxation of an excited nitromethane molecule in an argon bath. United States: N. p., 2015. Web. doi:10.1063/1.4904314.
Rivera-Rivera, Luis A., Wagner, Albert F., Sewell, Thomas D., & Thompson, Donald L. Pressure effects on the relaxation of an excited nitromethane molecule in an argon bath. United States. doi:10.1063/1.4904314.
Rivera-Rivera, Luis A., Wagner, Albert F., Sewell, Thomas D., and Thompson, Donald L. Wed . "Pressure effects on the relaxation of an excited nitromethane molecule in an argon bath". United States. doi:10.1063/1.4904314.
@article{osti_1393974,
title = {Pressure effects on the relaxation of an excited nitromethane molecule in an argon bath},
author = {Rivera-Rivera, Luis A. and Wagner, Albert F. and Sewell, Thomas D. and Thompson, Donald L.},
abstractNote = {Classical molecular dynamics simulations were performed to study the relaxation of nitromethane in an Ar bath (of 1000 atoms) at 300 K and pressures 10, 50, 75, 100, 125, 150, 300, and 400 atm. The molecule was instantaneously excited by statistically distributing 50 kcal/mol among the internal degrees of freedom. At each pressure, 1000 trajectories were integrated for 1000 ps, except for 10 atm, for which the integration time was 5000 ps. The computed ensemble-averaged rotational energy decay is similar to 100 times faster than the vibrational energy decay. Both rotational and vibrational decay curves can be satisfactorily fit with the Lendvay-Schatz function, which involves two parameters: one for the initial rate and one for the curvature of the decay curve. The decay curves for all pressures exhibit positive curvature implying the rate slows as the molecule loses energy. The initial rotational relaxation rate is directly proportional to density over the interval of simulated densities, but the initial vibrational relaxation rate decreases with increasing density relative to the extrapolation of the limiting low-pressure proportionality to density. The initial vibrational relaxation rate and curvature are fit as functions of density. For the initial vibrational relaxation rate, the functional form of the fit arises from a combinatorial model for the frequency of nitromethane "simultaneously" colliding with multiple Ar atoms. Roll-off of the initial rate from its low-density extrapolation occurs because the cross section for collision events with L Ar atoms increases with L more slowly than L times the cross section for collision events with one Ar atom. The resulting density-dependent functions of the initial rate and curvature represent, reasonably well, all the vibrational decay curves except at the lowest density for which the functions overestimate the rate of decay. The decay over all gas phase densities is predicted by extrapolating the fits to condensed-phase densities. (C) 2015 AIP Publishing LLC.},
doi = {10.1063/1.4904314},
journal = {Journal of Chemical Physics},
issn = {0021-9606},
number = 1,
volume = 142,
place = {United States},
year = {2015},
month = {1}
}

Works referenced in this record:

Pressure- and temperature-dependent combustion reactions
journal, April 2011


Mode specificity of vibrational energy relaxation of azulene in CO2 at low and high density
journal, July 1998


Collisional deactivation of vibrationally highly excited azulene in compressed liquids and supercritical fluids
journal, August 1996

  • Schwarzer, D.; Troe, J.; Votsmeier, M.
  • The Journal of Chemical Physics, Vol. 105, Issue 8
  • DOI: 10.1063/1.472180

Computer-Intensive Methods in Statistics
journal, May 1983


Theoretical studies of collisional relaxation of highly excited SO2 in an Ar bath
journal, January 1995

  • Lendvay, Gy�rgy; Schatz, George C.; Harding, Lawrence B.
  • Faraday Discussions, Vol. 102
  • DOI: 10.1039/fd9950200389

Direct study of energy transfer of vibrationally highly excited CS 2 molecules
journal, February 1985

  • Dove, J. E.; Hippler, H.; Troe, J.
  • The Journal of Chemical Physics, Vol. 82, Issue 4
  • DOI: 10.1063/1.448375

The structure of fluid argon from high-pressure neutron diffraction and ab initio molecular dynamics simulations
journal, August 1999

  • Pfleiderer, Till; Waldner, Isabella; Bertagnolli, Helmut
  • The Journal of Chemical Physics, Vol. 111, Issue 6
  • DOI: 10.1063/1.479539

Measurements of X-Ray Lattice Constant, Thermal Expansivity, and Isothermal Compressibility of Argon Crystals
journal, October 1966

  • Peterson, O. G.; Batchelder, D. N.; Simmons, R. O.
  • Physical Review, Vol. 150, Issue 2
  • DOI: 10.1103/PhysRev.150.703

The spectrum and ground state potential curve of Ar 2
journal, September 1976

  • Colbourn, E. A.; Douglas, A. E.
  • The Journal of Chemical Physics, Vol. 65, Issue 5
  • DOI: 10.1063/1.433319

Collisional Energy Transfer in Unimolecular Reactions: Direct Classical Trajectories for CH 4 ⇄ CH 3 + H in Helium
journal, May 2009

  • Jasper, Ahren W.; Miller, James A.
  • The Journal of Physical Chemistry A, Vol. 113, Issue 19
  • DOI: 10.1021/jp900802f

Vibrational Lifetimes and Spectral Shifts in Supercritical Fluids as a Function of Density:  Experiments and Theory
journal, March 2000

  • Myers, D. J.; Shigeiwa, Motoyuki; Fayer, M. D.
  • The Journal of Physical Chemistry B, Vol. 104, Issue 10
  • DOI: 10.1021/jp992717i

Collisional Energy Transfer Probability Densities P ( E , J ; E′ , J′ ) for Monatomics Colliding with Large Molecules
journal, October 2010

  • Barker, John R.; Weston, Ralph E.
  • The Journal of Physical Chemistry A, Vol. 114, Issue 39
  • DOI: 10.1021/jp106443d

Pressure dependent reactions for atmospheric and combustion models
journal, January 2008

  • Golden, David M.
  • Chemical Society Reviews, Vol. 37, Issue 4
  • DOI: 10.1039/b704259k

Connecting Chemical Dynamics in Gases and Liquids
journal, May 2006


Theoretical Studies of Solid Nitromethane
journal, September 2000

  • Sorescu, Dan C.; Rice, Betsy M.; Thompson, Donald L.
  • The Journal of Physical Chemistry B, Vol. 104, Issue 35
  • DOI: 10.1021/jp000942q

The role of local density in the collisional deactivation of vibrationally highly excited azulene in supercritical fluids
journal, November 1997

  • Schwarzer, D.; Troe, J.; Zerezke, M.
  • The Journal of Chemical Physics, Vol. 107, Issue 20
  • DOI: 10.1063/1.475038

Fast Parallel Algorithms for Short-Range Molecular Dynamics
journal, March 1995


Energy dependence of energy transfer in the collisional relaxation of vibrationally highly excited carbon disulfide
journal, October 1991

  • Lendvay, Gyorgy; Schatz, George C.
  • The Journal of Physical Chemistry, Vol. 95, Issue 22
  • DOI: 10.1021/j100175a061

Theoretical Unimolecular Kinetics for CH 4 + M ⇄ CH 3 + H + M in Eight Baths, M = He, Ne, Ar, Kr, H 2 , N 2 , CO, and CH 4
journal, June 2011

  • Jasper, Ahren W.; Miller, James A.
  • The Journal of Physical Chemistry A, Vol. 115, Issue 24
  • DOI: 10.1021/jp200048n

Collisional Relaxation of the Three Vibrationally Excited Difluorobenzene Isomers by Collisions with CO 2 :  Effect of Donor Vibrational Mode
journal, February 2008

  • Mitchell, Deborah G.; Johnson, Alan M.; Johnson, Jeremy A.
  • The Journal of Physical Chemistry A, Vol. 112, Issue 6
  • DOI: 10.1021/jp0771365

An efficient microcanonical sampling procedure for molecular systems
journal, January 1991

  • Schranz, Harold W.; Nordholm, Sture; Nyman, Gunnar
  • The Journal of Chemical Physics, Vol. 94, Issue 2
  • DOI: 10.1063/1.460008

Collisional energy transfer from highly vibrationally excited SF 6
journal, January 1993

  • Lendvay, György; Schatz, George C.
  • The Journal of Chemical Physics, Vol. 98, Issue 2
  • DOI: 10.1063/1.464328

Energy transfer of highly vibrationally excited 2-methylnaphthalene: Methylation effects
journal, July 2008

  • Hsu, Hsu Chen; Liu, Chen-Lin; Hsu, Yuan Chin
  • The Journal of Chemical Physics, Vol. 129, Issue 4
  • DOI: 10.1063/1.2953570

A simulation study of energy transfer in methyl isocyanide-inert gas collisions
journal, October 1995


Canonical dynamics: Equilibrium phase-space distributions
journal, March 1985


Reformulation and Solution of the Master Equation for Multiple-Well Chemical Reactions
journal, May 2013

  • Georgievskii, Yuri; Miller, James A.; Burke, Michael P.
  • The Journal of Physical Chemistry A, Vol. 117, Issue 46
  • DOI: 10.1021/jp4060704

Master Equation Analysis of Pressure-Dependent Atmospheric Reactions
journal, December 2003

  • Barker, John R.; Golden, David M.
  • Chemical Reviews, Vol. 103, Issue 12
  • DOI: 10.1021/cr020655d

Molecular dynamics study of the melting of nitromethane
journal, November 2003

  • Agrawal, Paras M.; Rice, Betsy M.; Thompson, Donald L.
  • The Journal of Chemical Physics, Vol. 119, Issue 18
  • DOI: 10.1063/1.1612915

Atomic Distribution in Liquid and Solid Neon and Solid Argon by Neutron Diffraction
journal, September 1958


Approximation for Rotation—Vibration Energy Level Sums
journal, September 1964

  • Whitten, G. Z.; Rabinovitch, B. S.
  • The Journal of Chemical Physics, Vol. 41, Issue 6
  • DOI: 10.1063/1.1726175

Vibrational Energy Transfer Modeling of Nonequilibrium Polyatomic Reaction Systems
journal, February 2001

  • Barker, John R.; Yoder, Laurie M.; King, Keith D.
  • The Journal of Physical Chemistry A, Vol. 105, Issue 5
  • DOI: 10.1021/jp002077f

Trajectory simulations of collisional energy transfer in highly excited benzene and hexafluorobenzene
journal, July 1995

  • Lenzer, Thomas; Luther, Klaus; Troe, Jürgen
  • The Journal of Chemical Physics, Vol. 103, Issue 2
  • DOI: 10.1063/1.470096

A unified model for simulating liquid and gas phase, intermolecular energy transfer: N 2 + C 6 F 6 collisions
journal, May 2014

  • Paul, Amit K.; Kohale, Swapnil C.; Pratihar, Subha
  • The Journal of Chemical Physics, Vol. 140, Issue 19
  • DOI: 10.1063/1.4875516

Simulations of the Vibrational Relaxation of I 2 in Xe
journal, October 2003

  • Li, Shenmin; Thompson, Ward H.
  • The Journal of Physical Chemistry A, Vol. 107, Issue 41
  • DOI: 10.1021/jp0345452

Calculation of Vibrational Relaxation Times in Gases
journal, October 1952

  • Schwartz, R. N.; Slawsky, Z. I.; Herzfeld, K. F.
  • The Journal of Chemical Physics, Vol. 20, Issue 10
  • DOI: 10.1063/1.1700221

Molecular-dynamics simulation of collisional energy transfer from vibrationally highly excited azulene in compressed CO2
journal, June 1998

  • Heidelbach, C.; Fedchenia, I. I.; Schwarzer, D.
  • The Journal of Chemical Physics, Vol. 108, Issue 24
  • DOI: 10.1063/1.476474

Dissociation, relaxation, and incubation in the high-temperature pyrolysis of ethane, and a successful RRKM modeling
journal, January 2005

  • Kiefer, J. H.; Santhanam, S.; Srinivasan, N. K.
  • Proceedings of the Combustion Institute, Vol. 30, Issue 1
  • DOI: 10.1016/j.proci.2004.08.215

Intermolecular Potential for the Hexahydro-1,3,5-trinitro-1,3,5- s -triazine Crystal (RDX):  A Crystal Packing, Monte Carlo, and Molecular Dynamics Study
journal, January 1997

  • Sorescu, Dan C.; Rice, Betsy M.; Thompson, Donald L.
  • The Journal of Physical Chemistry B, Vol. 101, Issue 5
  • DOI: 10.1021/jp9624865