Molecular dynamics modeling of hypersonic gas-phase and gas-surface reactions

T. E. Schwartzentruber, P. Norman, P. Valentini

Research output: Chapter in Book/Report/Conference proceedingConference contribution


Efforts to use molecular dynamics (MD) to develop both non-equilibrium dissociation models required in the shock layer as well as gas-surface interaction models specifically for surface catalysis will be summarized. First, an accelerated MD algorithm for dilute gases is presented, called the Event-Driven/Time-Driven (ED/TD) MD method. The method detects and moves molecules directly to their impending collision while still integrating each collision, including multi-body collisions, using conventional Time-Driven (TD) MD with an arbitrary inter-atomic potential. The simulation thus proceeds at time steps approaching the mean-collision-time. Preliminary nonequilibrium relaxation and normal shock wave simulations are in excellent agreement with direct simulation Monte Carlo (DSMC) results with large speedups over conventional TD MD, especially at low densities. Second, an MD simulation technique to study surface catalysis employing the ReaxFF inter-atomic potential is detailed. SiO2 surfaces are equilibrated with a dissociated gas mixture at various temperatures and pressures, establishing surface coverage. Rates of dominant reaction mechanisms, including adsorption, desorption, and E-R/L-H recombination, are then determined by counting individual events. The experimentally measured exponential dependence of recombination coefficient on temperature is well predicted by the MD simulations.

Original languageEnglish (US)
Title of host publication27th International Symposium on Rarefied Gas Dynamics - 2010, RGD27
Number of pages8
EditionPART 1
StatePublished - 2011
Event27th International Symposium on Rarefied Gas Dynamics, RGD27 - Pacific Grove, CA, United States
Duration: Jul 10 2011Jul 15 2011

Publication series

NameAIP Conference Proceedings
NumberPART 1
ISSN (Print)0094-243X
ISSN (Electronic)1551-7616


Other27th International Symposium on Rarefied Gas Dynamics, RGD27
Country/TerritoryUnited States
CityPacific Grove, CA


  • Gas-surface interaction
  • Heterogeneous catalysis
  • Molecular dynamics
  • Reactive force field


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