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Title: First-principles Monte Carlo simulations of reaction equilibria in compressed vapors

Predictive modeling of reaction equilibria presents one of the grand challenges in the field of molecular simulation. Difficulties in the study of such systems arise from the need (i) to accurately model both strong, short-ranged interactions leading to the formation of chemical bonds and weak interactions arising from the environment, and (ii) to sample the range of time scales involving frequent molecular collisions, slow diffusion, and infrequent reactive events. Here we present a novel reactive first-principles Monte Carlo (RxFPMC) approach that allows for investigation of reaction equilibria without the need to prespecify a set of chemical reactions and their ideal-gas equilibrium constants. We apply RxFPMC to investigate a nitrogen/oxygen mixture at T = 3000 K and p = 30 GPa, i.e., conditions that are present in atmospheric lightning strikes and explosions. The RxFPMC simulations show that the solvation environment leads to a significantly enhanced NO concentration that reaches a maximum when oxygen is present in slight excess. In addition, the RxFPMC simulations indicate the formation of NO2 and N2O in mole fractions approaching 1%, whereas N3 and O3 are not observed. Lastly, the equilibrium distributions obtained from the RxFPMC simulations agree well with those from a thermochemical computer code parametrizedmore » to experimental data.« less
 [1] ;  [2] ;  [3] ;  [4] ;  [5] ;  [1]
  1. Univ. of Minnesota, Minneapolis, MN (United States)
  2. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
  3. Argonne National Lab. (ANL), Argonne, IL (United States)
  4. ETH Zurich, Zurich (Switzerland)
  5. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
Publication Date:
OSTI Identifier:
Grant/Contract Number:
AC02-06CH11357; AC52-07NA27344
Published Article
Journal Name:
ACS Central Science
Additional Journal Information:
Journal Volume: 2; Journal Issue: 6; Journal ID: ISSN 2374-7943
American Chemical Society (ACS)
Research Org:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org:
National Science Foundation (NSF); USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Scientific User Facilities Division; Argonne National Laboratory - Argonne Leadership Computing Facility
Country of Publication:
United States