Nanojoule Adsorption Calorimetry. Design, Construction, Novel Evaluation Approach, Software Development, Characterization, and Exemplary Measurements

The interaction of single molecules with surfaces as well as the interaction between surfaces, i.e., interfaces, are often of great interest and thus a vast field of applied sciences arises therefrom. Most ultra high vacuum based surface science techniques are only able to deliver information about an already formed interface. The desire for knowledge of the energetics describing the processes during the formation of such a contact layer motivates the usage of nanojoule adsorption calorimetry. This work presents the construction of the experimental setup necessary to study the coverage dependent heat of adsorption. The setup is optimized for investigations involving the adsorption of metal atoms on organic thin films and of large organic molecules on surfaces of single crystalline metals. The software developed for this work and used for data treatment is also covered by this thesis. In this respect, the user interface as well as the program code processing the data are both well discussed. The characterization of the components involved in calorimetric experiments is presented in detail later in this work. Finally, selected experiments involving the adsorption of magnesium, zinc, copper, and calcium on the pristine and cleaned detector surface as well as on 3,4,9,10-perylene-tetracarboxylic dianhydride, tetraphenylporphyrin, alpha-sexithiophene, and poly(3-hexylthiophene) are exemplarily discussed. This paper is completed by design drawings of the constructed elements for this work, the source code of the data treatment program developed for this work, an overview of the investigated systems, and the parameters used to operate the scientific equipment. Considering all individual aspects presented in this dissertation conjoined, the scientific framework necessary to study coverage dependent heats of adsorption precisely is established

Strangeness Suppression in Proton-Proton Collisions

We analyse strangeness production in proton-proton (pp) collisions at SPS and RHIC energies, using the recently advanced NeXus approach. After having verified that the model reproduces well the existing data, we interpret the results: strangeness is suppressed in proton-proton collisions at SPS energy as compared to electron-positron (e+e-) annihilation due to the limited masses of the strings produced in the reaction, whereas high energy pp and e+e- collisions agree quantitatively . Thus strangeness suppression at SPS energies is a consequence of the limited phase-space available in string fragmentation.Comment: 7 Figures, 4 Page

Nanojoule Adsorption Calorimetry. Design, Construction, Novel Evaluation Approach, Software Development, Characterization, and Exemplary Measurements

The interaction of single molecules with surfaces as well as the interaction between surfaces, i.e., interfaces, are often of great interest and thus a vast field of applied sciences arises therefrom. Most ultra high vacuum based surface science techniques are only able to deliver information about an already formed interface. The desire for knowledge of the energetics describing the processes during the formation of such a contact layer motivates the usage of nanojoule adsorption calorimetry. This work presents the construction of the experimental setup necessary to study the coverage dependent heat of adsorption. The setup is optimized for investigations involving the adsorption of metal atoms on organic thin films and of large organic molecules on surfaces of single crystalline metals. The software developed for this work and used for data treatment is also covered by this thesis. In this respect, the user interface as well as the program code processing the data are both well discussed. The characterization of the components involved in calorimetric experiments is presented in detail later in this work. Finally, selected experiments involving the adsorption of magnesium, zinc, copper, and calcium on the pristine and cleaned detector surface as well as on 3,4,9,10-perylene-tetracarboxylic dianhydride, tetraphenylporphyrin, alpha-sexithiophene, and poly(3-hexylthiophene) are exemplarily discussed. This paper is completed by design drawings of the constructed elements for this work, the source code of the data treatment program developed for this work, an overview of the investigated systems, and the parameters used to operate the scientific equipment. Considering all individual aspects presented in this dissertation conjoined, the scientific framework necessary to study coverage dependent heats of adsorption precisely is established