Scattering of Hyperthermal Effusive N and N2 Beams at Metal Surfaces

Abstract

General rightsIt is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), other than for strictly personal, individual use, unless the work is under an open content license (like Creative Commons). Disclaimer/Complaints regulationsIf you believe that digital publication of certain material infringes any of your rights or (privacy) interests, please let the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the material inaccessible and/or remove it from the website. Please Ask the Library: http://uba.uva.nl/en/contact, or a letter to: Library of the University of Amsterdam, Secretariat, Singel 425, 1012 WP Amsterdam, The Netherlands. You will be contacted as soon as possible. AbstractMolecular beam experiments with specially prepared beams allow the study of the interaction of very reactive species at surfaces. In the present case the focus is primarily on the interaction of N-atoms with surfaces. In this chapter questions that will be addressed include: -What is the scattering pattern and energy transfer of N-atoms at surfaces? -Can adsorption of N-atoms lead to a passive layer that is not reactive to incident N-atoms? -Conversely, can N-atoms remove N-atoms in an Eley-Rideal or hot atom reaction?-Does the electronic state of the atoms matter? -Can the interaction already be described by state-of-time art theory? The methods used will be introduced with examples of fast Ar scattering from Ag(111). Subsequently, the interaction of N-atoms with Ag(111) and Ru(0001) will be discussed in order to address the questions listed above. Some work with N 2 will also be shown. Keywords IntroductionThe fate of a chemical reaction is often determined by the availability of energy and the reactivity of the species involved. Energy, both translational and internal, can allow the reactants to overcome activation barriers and possible endoergicity of the reaction. The most probable path on the potential energy surface describing the reaction is thus governed by availability of energy. Working with excess translational energy limits reaction yields but allows exploration of the nature of the potential energy surfaces involved. Scattering experiments were built to carry out such studies both in gas-phase collisions and in atom/molecule surface collisions. In this chapter we focus on the latter case for experimental studies involving reactive atoms and molecules and we compare these results to similar studies with inert noble gas atoms for calibration.The importance of surface scattering experiments was already realized in the 1970's [1][2][3][4]. From the early work two regimes are identified and the corresponding terms thermal scattering and structure scattering were coined. In the first case the processes are dominated by an energy constraint and the thermal energy of the surface is an important parameter. In addition, parallel momentum conservation applies. In the second case the dynamics at the surf...

Nitrogen Scattering at Ru(0001) Surfaces

“…2. In the case of the nitrogen plasma the energy distributions for the current and earlier measurements are quite similar; only the N to N 2 ratio in the incident beam has changed (see [34]). In contrast, the current Ar beam energy distribution shows a higher average energy and a broader energy width compared to the previous studies.…”