1. NO chemisorption dynamics on thick FePc and ttbu-FePc films
- Author
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Gary C. Poon, Sarah R. Bishop, Forest I. Bohrer, Ngoc L. Tran, Tyler J. Grassman, William C. Trogler, and Andrew C. Kummel
- Subjects
Materials science ,Inorganic chemistry ,Analytical chemistry ,General Physics and Astronomy ,Substrate (electronics) ,Metal ,Adsorption ,Reflection (mathematics) ,Chemisorption ,visual_art ,visual_art.visual_art_medium ,Physical and Theoretical Chemistry ,Thin film ,Beam energy ,Saturation (magnetic) - Abstract
The NO chemisorption dynamics on ordered multilayer iron phthalocyanine (FePc) and quasiamorphous multilayer tetra-t-butyl FePc (ttbu-FePc) films on a Au(111) substrate was investigated using the King and Wells reflection technique. The NO zero coverage or initial sticking probabilities (S(0)) were measured as a function of sample temperature (T(s)) and beam energy (E(i)). The experimental results for both films show a monotonic decrease in S(0) with increasing T(s) and E(i) consistent with NO adsorption occurring via a multiple pathway precursor-mediated mechanism in which the adsorbate initially physisorbs to the FePc organics, diffuses, and chemisorbs to the Fe metal center. The saturation coverage is 3% for the multilayer FePc surface and only 2% for the multilayer ttbu-FePc surface consistent with NO chemisorption occurring only on the Fe metal, where NO chemisorbs to 100% of the surface Fe metal centers. The reduced saturation coverage in the ttbu-FePc film is attributed to fewer Fe metal centers in the less dense ttbu-FePc films. A comparison of NO sticking on a multilayer FePc/Au(111) film with NO sticking on a monolayer FePc/Au(111) film shows that S(0) is greater on the multilayer FePc film for all T(s) and E(i), consistent with an increase in collision inelasticity for NO/multilayer FePc/Au(111).
- Published
- 2009