| dc.contributor.advisor | Wodtke, Alec Prof. Dr. | |
| dc.contributor.author | Kaufmann, Sven | |
| dc.date.accessioned | 2018-03-28T09:01:21Z | |
| dc.date.available | 2018-03-28T09:01:21Z | |
| dc.date.issued | 2018-03-28 | |
| dc.identifier.uri | http://hdl.handle.net/11858/00-1735-0000-002E-E3A5-8 | |
| dc.identifier.uri | http://dx.doi.org/10.53846/goediss-6813 | |
| dc.identifier.uri | http://dx.doi.org/10.53846/goediss-6813 | |
| dc.language.iso | eng | de |
| dc.publisher | Niedersächsische Staats- und Universitätsbibliothek Göttingen | de |
| dc.rights.uri | http://creativecommons.org/licenses/by-nc-nd/4.0/ | |
| dc.subject.ddc | 540 | de |
| dc.title | Generation of H-Atom Pulses and Associative Desorption of Hydrogen Isotopologues from Metal Surfaces | de |
| dc.type | doctoralThesis | de |
| dc.contributor.referee | Wodtke, Alec Prof. Dr. | |
| dc.date.examination | 2017-10-11 | |
| dc.description.abstracteng | Part I of this work introduces a technique for the generation of H-atom pulses with
unprecedented time resolution. In part II an extensive study of the associative desorption
reaction of hydrogen isotopologues from metal surfaces is presented.
Part I: Generation of H-Atom Pulses. Short intense pulses are of fundamental importance for
scientific studies of dynamics. Equivalent-time experiments relying on the pump-probe
technique are conducted routinely in physics, chemistry and biology. In contrast to the
light pulses often utilized in such studies, chemical reactions are generally initiated by
collisions. While methods for the generation of matter pulses exist, their performance is
significantly inferior to modern laser pulses. Here, a new photolysis technique is introduced
to produce pulses of neutral matter, which relies on well-known simple physical principles.
This technique is implemented for the rst time and achieves an H-atom pulse duration
of ~1.2 ns (time resolution of 0.03%), which corresponds to an improvement by one order
of magnitude compared to established photolysis methods. From the full mathematical
description of the concept presented here further improvements are predicted. These
include the reduction of the pulse duration below the nanosecond timescale as well as a
significant increase in the absolute pulse intensity. This new method extends the scientific
toolbox and enables a new class of future experiments which involve time-resolved collisions
of neutral matter. Part II: Hydrogen Permeation. The interaction of hydrogen with metal surfaces is one of the
most fundamental reactions in surface chemistry. The H2/Cu(111) system serves as a
benchmark for theoretical studies, which are nowadays able to describe the reactivity of
certain systems with an accuracy of 1 kcal/mole, often referred to as "chemical accuracy".
This study reports an extensive set of experimental data of the post-permeation associative
desorption of H2, HD and D2 from single crystal surfaces of Cu(111), Cu(211) and Au(111).
By invoking the principle of detailed balance initial state resolved reaction probability
curves are obtained, which are compared to selected studies.
For the H2/Cu(111) system small but significant deviations to the literature are found
which are attributed to an improved calibration procedure in this work. The Cu(211)
data revealed systematic differences to the Cu(111) sample on the order of the calibration
uncertainty, which necessitated the direct comparison of both copper facets under the same
experimental conditions. Furthermore, evidence for an additional desorption channel on
both facets is presented and analyzed quantitatively. Several possible reaction mechanisms
are speculated upon which include argumentations as to why this had not been reported
in previous work.
Finally, for the highly activated H2/Au(111) system the presented results provide a
quantum-state-resolved experimental data set to which theoretical studies can be compared.
In this data set an isotope-specific effect is observed, which questions the general
validity of the adiabatic approximation generally assumed in description of the interaction
of hydrogen with noble metal surfaces. | de |
| dc.contributor.coReferee | Schwarzer, Dirk Prof. Dr. | |
| dc.contributor.thirdReferee | Troe, Jürgen Prof. Dr. | |
| dc.contributor.thirdReferee | Schroeder, Jörg Prof. Dr. | |
| dc.contributor.thirdReferee | Mata, Ricardo Prof. Dr. | |
| dc.contributor.thirdReferee | Zeuch, Thomas PD Dr. | |
| dc.subject.eng | Photolysis | de |
| dc.subject.eng | Desorption | de |
| dc.subject.eng | Detailed Balance | de |
| dc.subject.eng | Permeation | de |
| dc.subject.eng | Hydrogen | de |
| dc.subject.eng | Metal Surfaces | de |
| dc.subject.eng | Hydrogen Pulse | de |
| dc.identifier.urn | urn:nbn:de:gbv:7-11858/00-1735-0000-002E-E3A5-8-3 | |
| dc.affiliation.institute | Fakultät für Chemie | de |
| dc.subject.gokfull | Chemie (PPN62138352X) | de |
| dc.identifier.ppn | 1016715285 | |