Olivier Ayissi, Serge
(2008)
Simulation of chiral ordering process in the adsorption of chiral organic molecules on metal surfaces by Monte Carlo methods.
PhD thesis, University of Liverpool.
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Abstract
Experimental observations have shown that haloalkane molecules, e.g. l-cWorododecane, physisorbed on Si(111)-(7 x 7) self-assemble to form dimers stable to 100° C which corral silicon adatoms. The corral size is governed by the haloalkane chain-length. Spectroscopic and theoretical evidence shows that the haloalkane dimer induces electron transfer to the corralled adatom. The enclosed silicon adatom, within a bistable dimeric corral of self-assembled chlorododecane molecules, switches its energy levels permanently (Type-II corrals) or discontinuously (Type-I corrals). Both types of corral, switching and stable, can be seen to alter the local surface charge distribution. Density Functional Theory and electron transport (STM) simulations of the switch and the stable molecular configurations can help the theoretical understanding of both phenomena in order to characterized the exact molecular conformations that produce field effects to the corralled silicon adatom and local surface charge distribution. Chiral heterogeneous catalysts are mostly fabricated from chiral molecules on a metal support. They playa crucial role in intermediate reactions in the fabrication of pharmacies, itself and important part of today's health econolPY. However, the key parameters in the fabrication of these catalysts, a requirements for their rational design, are still poorly understood despite years of experimental research. In essence, such an understanding can only come from high-level simulations. Here, we present the first predictions about the structure of such a catalyst, tartaric acid on a copper support, over the whole phase space of temperature and coverage. Interestingly, we find that molecular vibrations playa key role in the ensuing ordered structures, and that tuning the fabrication temperature should allow for a wide range of molecular separations, which can be targeted at specific molecules and reactions in chiral heterogeneous catalysis.
| Item Type: | Thesis (PhD) |
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| Depositing User: | Symplectic Admin |
| Date Deposited: | 20 Oct 2023 09:25 |
| Last Modified: | 20 Oct 2023 09:28 |
| DOI: | 10.17638/03174589 |
| Copyright Statement: | Copyright © and Moral Rights for this thesis and any accompanying data (where applicable) are retained by the author and/or other copyright owners. A copy can be downloaded for personal non-commercial research or study, without prior permission or charge |
| URI: | https://livrepository.liverpool.ac.uk/id/eprint/3174589 |
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