Subscriber access provided by TULANE UNIVERSITY
C: Surfaces, Interfaces, Porous Materials, and Catalysis 2
Energy Dissipation Effects on the Adsorption Dynamics of N on W(100) Alejandro Peña-Torres, H. Fabio Busnengo, Joseba Inaki Juaristi, Pascal Larregaray, and Cedric Crespos J. Phys. Chem. C, Just Accepted Manuscript • DOI: 10.1021/acs.jpcc.8b10173 • Publication Date (Web): 10 Jan 2019 Downloaded from http://pubs.acs.org on January 20, 2019
Just Accepted “Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted online prior to technical editing, formatting for publication and author proofing. The American Chemical Society provides “Just Accepted” as a service to the research community to expedite the dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully peer reviewed, but should not be considered the official version of record. They are citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or consequences arising from the use of information contained in these “Just Accepted” manuscripts.
is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Published by American Chemical Society. Copyright © American Chemical Society. However, no copyright claim is made to original U.S. Government works, or works produced by employees of any Commonwealth realm Crown government in the course of their duties.
Page 1 of 18 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
The Journal of Physical Chemistry
Energy Dissipation Effects on the Adsorption Dynamics of N2 on W(100) A. Pe˜na-Torres,∗,†,‡ H.F. Busnengo,¶ J.I. Juaristi,§,k,‡ P. Larregaray,†,⊥ and C. Crespos†,⊥ †Universit´e Bordeaux, ISM, UMR5255, F-33400 Talence, France ‡Centro de F´ısica de Materiales CFM/MPC (CSIC-UPV/EHU), Paseo Manuel de Lardizabal 5, 20018 Donostia-San Sebasti´an, Spain ¶Instituto de F´ısica de Rosario (CONICET-UNR) and Facultad de Ciencias Exactas, Ingenier´ıa y Agrimensura, Universidad Nacional de Rosario, Avenida Pellegrini 250, 2000 Rosario, Argentina §Donostia International Physics Center (DIPC), Paseo Manuel de Lardizabal 4, 20018 Donostia-San Sebasti´an, Spain kDepartamento de F´ısica de Materiales, Facultad de Qu´ımicas (UPV/EHU), Apartado 1072, 20080 Donostia-San Sebasti´an, Spain ⊥CNRS, ISM, UMR5255, F-33400 Talence, France E-mail:
[email protected] Abstract
ity, including dissociative and non-dissociative mechanisms, is enhanced when molecules can lose energy through surface phonons and electronic excitations. However, the energy exchange with phonons has a larger influence in the adsorption probability than electron-hole pair excitations. Non-dissociative molecular adsorption only takes place when such energy dissipation channels are included in the simulations, underlying the importance of GLO and LDFA models in such theoretical studies.
Adsorption dynamics of N2 on W(100) surface is studied by means of quasi-classical trajectories making use of a six-dimensional potential energy surface (PES) obtained from density functional theory (DFT) calculations. In our simulations, van der Waals interactions are accounted for by using the vdW-DF2 functional. In view of the comparison with experiments, we show that this leads to a good description of the adsorption dynamics, providing a significant improvement with respect to semilocal exchange-correlation functionals used in the past. Particular emphasis is placed on the description of non-activated pathways leading to either dissociation or molecular adsorption. Dynamics calculations are performed within the generalized Langevin oscillator (GLO) model in order to simulate the energy exchange between molecule and surface atoms. Electron-hole (e − h) pairs excitations are also implemented in the dynamics via the local density friction approximation (LDFA). Overall adsorption probabil-
1
Introduction
The reactivity of molecules interacting with metallic surfaces has been extensively studied over the last years, mainly due to its importance in heterogeneous catalytic processes. Over the last decades, remarkable progress has been made in both experimental 1–6 and theoretical 7–25 techniques in order to achieve accurate description of molecule-surface elementary reactions dynamics. In this respect, one
ACS Paragon Plus Environment
1
The Journal of Physical Chemistry 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Page 2 of 18
corrugation reducing procedure (CRP). 43,44 In order to include energy exchange with lattice vibrations and surface temperature effects, a generalized Langevin oscillator (GLO) model was implemented in the simulations. 45–50 Energy dissipation effects caused by electron-hole (e − h) pairs excitations may also play a role, and were accounted for by means of the local density friction approximation (LDFA). 12,51 Although it has been shown that for this particular system the reactivity is not much affected by this effect when PW91 or RPBE functionals are used, 52 changes in the topology of the PES induced by the vdW forces might lead to e − h pair excitations having a more significant role in the reaction dynamics. In the following, a detailed description of the dissociative and non-dissociative adsorption mechanisms is presented in relation with the effects of energy dissipation channels. The paper is organized as follows. In Sec. 2, we present the technical details of the six-dimensional-PES (6D-PES) together with the computational details for all the dynamics calculations performed (i.e. BOSS, GLO, LDFA). In Sec. 3, we characterize the interaction between the N2 molecules and the W(100) surface by performing BOSS calculations and carefully analyzing the reaction paths leading to dissociation and comparing the results to those obtained in previous works. 32 In Sec. 4 we present the results for the dynamics when energy dissipation channels are implemented. A comparison with experimental data is also reported. Finally, we conclude in Sec 5.
of the most representative examples is the N2 molecule reacting with metallic surfaces, as its dissociation is the rate-limiting step in the ammonia synthesis process. 26 As a matter of fact, reactive scattering of N2 on tungsten surfaces has also attracted attention due to large crystallographic anisotropies observed in early experiments, 27,28 feature that has been theoretically investigated as well. 29 In the present study, a special focus is made on the balance between dissociative and nondissociative adsorption of N2 on a W(100) surface. This has been widely addressed in the past, on one hand by molecular beam experiments 30,31 and on the other hand by dynamics studies using multidimensional potential energy surfaces (PES) based on density functional theory (DFT). 32,33 In these works, various exchange-correlation (XC) functionals were used to obtain the DFT energies for the PES (namely PW91 34 and RPBE 35 ), and clear discrepancies were shown in the dissociation probability between theory and experiments, particularly when molecules are colliding the W surface with low translational energies (i.e.
