Langevin and Fokker-Planck Analyses of Inhibited Molecular Passing Processes Controlling Transport and Reactivity in Nanoporous Materials

Chi-Jen Wang, David M. Ackerman, Igor I. Slowing, and James W. Evans
Phys. Rev. Lett. 113, 038301 – Published 14 July 2014
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Abstract

Inhibited passing of reactant and product molecules within the linear pores of nanoporous catalytic materials strongly reduces reactivity. The dependence of the passing propensity P on pore radius R is analyzed utilizing Langevin dynamics to account for solvent effects. We find that P(RRc)σ, where passing is sterically blocked for RRc, with σ below the transition state theory value. Deeper insight comes from analysis of the corresponding high-dimensional Fokker-Planck equation, which facilitates an effective small-P approximation, and dimensional reduction enabling utilization of conformal mapping ideas. We analyze passing for spherical molecules and also assess the effect of rotational degrees of freedom for elongated molecules.

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  • Received 10 May 2014

DOI:https://doi.org/10.1103/PhysRevLett.113.038301

© 2014 American Physical Society

Authors & Affiliations

Chi-Jen Wang1,2, David M. Ackerman1, Igor I. Slowing1,3, and James W. Evans1,4

  • 1Ames Laboratory-U.S. DOE, Iowa State University, Ames, Iowa 50011, USA
  • 2Department of Mathematics, Iowa State University, Ames, Iowa 50011, USA
  • 3Department of Chemistry, Iowa State University, Ames, Iowa 50011, USA
  • 4Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA

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Issue

Vol. 113, Iss. 3 — 18 July 2014

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