Dissociative adsorption dynamics of nitrogen on a Fe(111) surface

Abstract

We study the dissociative adsorption dynamics of N on clean bcc Fe(111) surfaces. We base our theoretical analysis on a multidimensional potential energy surface built from density functional theory. The dissociative sticking probability is computed by means of quasi-classical trajectory calculations. For normal incidence and impact energies of the order of a few eV, our theoretical results agree well with existing experimental values. For these energies, the dynamics of the dissociated molecules shows that dissociation is a direct process that follows narrow paths in the multidimensional space. For lower energies of the beam, this direct process is not enough to explain the measured values. A better agreement with the experiment is obtained if we increase the surface temperature to promote the transfer to dissociation of molecules previously trapped. Most of the molecules dissociate very close to the Fe(111) third layer atoms and with an orientation parallel to the surface. A comparison between the dissociation of N on Fe(111) and Fe(110) highlights the role of the different energy barriers in both surfaces.

Quantum Effects in the Dissociative Chemisorption of N2 on Fe(111): Full-Dimensional Quantum Dynamics and Quasi-Classical Trajectory Study

“…We compared the current results with the experimental and previous theoretical results, as shown in Figure . Owing to the large numerical parameters for convergence and huge computational capacity, the quantum dynamical dissociation probabilities for E c > 1.6 eV were not obtained in the current work.…”

“…The Fe(111) surface is the most open and reactive surface of the low-index bcc iron faces, compared with the reactivities of Fe(100) and Fe(110). ,, Four molecular chemisorbed states for N 2 on Fe(111), namely, γ, δ, ε, and α, were identified in previous experimental and theoretical adsorption studies. ,, The α state and ε state are parallel to the surface plane with a stretched molecular bond length. In particular, the ε state is on the fcc site, and the α state is on the bridge state with the deepest adsorption well, in which both nitrogen atoms interact with iron to form a π-bonded surface complex .…”

“…The role of iron is to lower the dissociation barrier of the nitrogen–nitrogen triple bond. Thus, the DC of N 2 on Fe surfaces is a hot topic for both experimental and theoretical research. − …”

“…However, Mortensen et al claimed that it is a complicated dissociation path for the dissociative adsorption of N 2 on Fe(111) based on static density functional theory (DFT) investigations . Recently, Norsir et al performed quasi-classical trajectory (QCT) dynamical calculations on a six-dimensional potential energy surface (PES) of N 2 dissociation on Fe(111), which was constructed by the corrugation-reducing procedure (CRP) interpolation method based on the DFT data points . The calculated QCT results have significant deviation from the experimental values, probably due to the insufficient accuracy of the PES and the tunneling and/or zero-point energy (ZPE) effects neglected in the QCT method.…”

Hydrogen chloride adsorption on large defective PAHs modeling soot surfaces and influence on water trapping: A DFT and AIMD study

“…surface reactivity studies. 50 Indeed, using AIMD simulations allows to take into account the possible influence of the temperature on the HCl adsorption process. It also avoids a tedious explicit characterization of the possible energy barriers that may exist along the reaction paths of the adsorption process, as evidenced in previous studies of the reactivity of similar surfaces with H 2 O and O 2 molecules.…”