Electric Field-Induced Dissociation of NH$_3$ on Ru(0001) from First Principles

ORAL

Abstract

Recent experimental evidence suggests that an applied electric field from an STM tip can induce rapid dissociation of NH3 on a Ru(0001) surface. Here, density functional theory calculations, within the generalized gradient approximation, are used to understand the experimental observations and develop a clear picture of this complex reaction. The desorption and dissociation thresholds are found to occur at E=-0.06 V/\AA and E=0.12 V/\AA, respectively, in good agreement with experiment. Calculation of the energy barrier along a potential reaction pathway indicates a decrease of 0.50 eV in the barrier at the dissociation threshold. A field-induced softening of the ammonia umbrella mode is found to explain the initial dissociation. It is concluded that an applied electric field greatly enhances the dissociation reaction rate through a reduction of the reaction energy barrier.

*We acknowledge support from DOE and DARPA. Computational resources provided by NERSC.

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Authors

  • Aaron Sisto

    • Department of Mechanical Engineering, Purdue University, West Lafayette, IN 47906

  • Alexey T. Zayak

    • Molecular Foundry, LBNL, Berkeley, CA 94720, Department of Electrical Engineering and Computer Sciences, UC Berkeley, CA 94720, USA

  • Jeff Neaton

    • Molecular Foundry, LBNL, Berkeley, CA 94720
    • Molecular Foundry, LBNL
    • Molecular Foundry, Lawrence Berkeley National Lab
    • Lawrence Berkeley National Laboratory
    • Molecular Foundry, Lawrence Berkeley National Laboratory