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Faculty of Chemistry and Mineralogy |
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Research Activities at the Faculty |
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Reports of the Institutes and Departments |
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Research Activities at the Faculty |
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The Faculty of Chemistry and Mineralogy can look back on a successful year of research in 1999, and it shaped many of the research activities at the University of Leipzig. The different institutes work on the following complex research programmes: |
Postgraduate Research Units |
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Postgraduate Research Unit "Physical Chemistry of
Interfaces"
Head: Prof. R. Szargan (Wilhelm Ostwald Institute of Physical and Theoretical Chemistry) The aim of the postgraduate research unit is to run an interdisciplinary training project which helps a large number of postgraduates to achieve their doctorate during a three-year period of post graduate training as part of a complex research programme. The research programme contains the topics "Interfaces of Porous Solids", "Semiconductor Interfaces" and "Fluid Interfaces". It involves the usage of a representative arsenal of instrumental and theoretical methods, and is devoted to the diversity of physical phenomena and chemical conversions of interfaces of all possible phase combinations. A postgraduate training programme studying the "Theoretical Fundamentals of Interfaces", "Experimental Methods for the Characterisation of Interfaces" and "Technical and Analytical Applications of Interface Phenomena" as well as a series of colloquia featuring renowned visiting scientists are organised for the doctoral candidates. The institutions involved include the Institutes of Physical and Theoretical Chemistry, Technical Chemistry, Analytical Chemistry, and Organic Chemistry, as well as the interdisciplinary group Time Resolved Spectroscopy, all of which are based at the Faculty of Chemistry and Mineralogy, as well as at the Institute of Experimental Physics I at the Faculty of Physics and Geosciences, and the Institute of Non-classical Chemistry at the University of Leipzig. 20 professors (who submit the applications), nine associated professors, three post-docs (two grant-holders and one associated post-docs), 23 doctoral candidates (including 14 grant-holders and nine associated members supported by other funding programmes) form the research unit. In 1999, 11 doctoral programmes were successfully completed on schedule.
Postgraduate Research Unit: "Mechanistic and Application
Aspects
of Non-conventional Oxidation Reactions"
Non-conventional aspects of a central chemical reaction, namely oxidation, are being studied in an interdisciplinary research group, and form the core of a modern, stimulating postgraduate training programme. The central aspects of the research programme are the development of new oxidation agents (heterometallic complexes, benzene perselenic acid, bisazidoiodosobenzene, 3-hydro-peroxysultime and sultame, electrophilic amination with a homochiral nitrenoid, O-sulphonyl-oxime and a chloronitroso compound), their application in syntheses, enzymatic oxidation reactions (cytochrome P450, independent and dependent monooxygenases), including the characterisation and structural determination of enzymes, and the study of reactive oxygen species in living organism and in inflammable processes. The postgraduate research unit offers scholarship-holders and associate members a research-based training programme which comprises the main chemistry subjects (inorganic chemistry, organic chemistry, physical chemistry), pharmaceutical chemistry, biochemistry (including molecular biology), biophysics and environmental chemistry. Hence, in addition to the topic of their own dissertation, scholarship-holders and associate members undergo further interdisciplinary training. The training programme includes lectures, colloquia with prominent visiting scientists, a programme of seminars, and practical courses in the laboratories of the groups involved. 13 professors and Habilitation candidates, one post-doc, 11 scholarship-holders and six associate members from the Faculty of Biology, Pharmacy and Psychology, the Faculty of Chemistry and Mineralogy, and the Faculty of Medicine form the postgraduate research unit. |
Collaborative Research Centre 294 |
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Collaborative Research Centre 294: "Molecules in Interaction with
Interfaces"
Head: Prof. D. Michel (Faculty of Physics and Geosciences, Institute of Experimental Physics II)
Sub-project D1: Studies of elementary steps of
heterogeneous catalysis - elucidation of the reaction mechanism of
n-butene-isomerisation on ferrierite and
similar zeolites. The mechanism of isomerisation of n-butene to i-butene on zeolites is the subject of controversial discussion. Initial findings show that a mainly mono-molecular mechanism takes place on ferrierite, whereas on ZSM-5 zeolites the dimerisation of iso-Butene to C8-hydrocarbons occurs in a subsequent reaction. |
Centres of Excellence |
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Centre of Excellence: "Chemical Signal and Biological
Answer"
Head: Prof. Peter Welzel (Institute of Organic Chemistry)
This centre of excellence is run by a team from three faculties (Chemistry and Mineralogy; Biology, Pharmacy and Psychology; Medicine). The scientific objective is to improve the understanding of the interaction between active agents (chemical signals) and their targets, which are usually based on highly selective recognition mechanisms. The centre of excellence has already four successful years. The period 1996-99 produced a wealth of scientific findings and activities in the form of:
On 23/24 April 1998, the work of the centre of excellence was refereed by a commission from the DFG (German Science Foundation). The inspection went very well, and it was announced by the DFG in November that funding had been granted almost in full for the continuation of the project's work. The Centre of Excellence will now be funded for another two years. The participants have agreed to make every effort to work towards the establishment of an SFB (Collaborative research centre) on the basis of the work successfully carried out so far. Period of funding: second phase, 01 January 1999 - 31 December 2000
Centre of Excellence: "Phenomena at Miniaturisation
Limits"
Sub-project K: "Dimension Quantisation in
III-V-Heterostructures" The project focuses on the study of MOVPE monolayer epitaxial growth of InAs, InP, GaP and AlP in various AIII-BV-barrier materials. Excitonic states must be assumed in such layer arrangements. Exact knowledge of the localisation energy of the excitons and their radiating transition probability, the oscillator strength, is of general importance for the usage of corresponding ultra-thin layer arrangements in the optically active area of special laser and detector components. The first semiconductor lasers with monolayers in the active area have been successfully tested. Period of funding: January 1996 - December 2000
Sub-project L: "III-V-semiconductor
Microresonators with
Ultra-thin Isovalent Layers" This project studies the coupling of resonator modes with excitation states in individual and multiply repeated isovalent atomic layers in AIII-BV-semiconductor microresonators. The key question to be answered in this project is whether the absorption and
emission of photons can be amplified by electronic transitions in such a
semiconductor layer by coupling with the resonator modes of a planar semiconductor
microresonators in a similar way to that known from quantum trench
effects.
Sub-project P: "Organic Nanometre Layers on
III-V-semiconductor Surfaces" The goals are to explain the chemical bonds of alkane thiolate molecules on semiconductor surfaces, the structure of the resulting self-organising organic adsorbate layers, and the influence of the surface structure of the crystalline substrate. Another aim is the defined structuring of organic monolayers by means of electron-based methods. In 1999 the study of SAMs on (110)-surfaces on various III-V-semiconductors using X-ray absorption was continued at BESSY (Berlin), and significant orientation dependencies on the surface structure were found. Using a UHV-STM, thiol molecules on InP(110) were successfully detected in various phases of the formation of SAMs. By using STM, trenches with a lateral width of 20nm in the SAMs were produced and shown. |
Leipzig Interdisciplinary Semiconductor Research Team |
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FAHL - Leipzig Interdisciplinary Semiconductor Research Team
Head: Prof. K. Bente (Institute of Mineralogy, Crystallography and Materials Science) Methodological co-operation (HRTEM) with the centre of excellence "Phenomena at Miniaturisation Limits". |
EU funded Research Projects |
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EU funded research project: Thematic Network "Glow Discharge
Spectroscopy for Spectrochemical Analysis"
Head: Prof. J. A. C. Broekaert (Institute of Analytical Chemistry) The project studies the possibilities of glow discharge in particular with respect to its usage for the analysis of environmentally relevant samples and the analysis of new materials. Work focuses on analysing ceramic powders using plasma spectrometry (Leipzig) and glow discharge (IFW e.V., Dresden), as well as the determination of environmental pollutants in co-operation with the University of Oviedo (Spain). Period of funding: 1 January 1999 - 31 December 2001
EU funded research project: "Aldehydes"
The simultaneous trace determination of aldehydes and ketones in various environmental matrices is mainly carried out using the DNPH method, in which the carbonyl compounds are converted into the corresponding hydrazones in the presence of acid with 2,4-dinitrophenylhydrazine, and then determined using HPLC. Involving nine partners from six different countries, the aim of this EU project is to overcome the existing weak points of this technique stemming from interference with ozone or nitrogen oxides, as well as from the diversity of possible unsaturated carbonyl compounds. The Leipzig team is developing and testing a gas-chromatographic method of determination independent of HPLC involving the usage of new dosing techniques. Period of funding: December 1997 - November 2000 |
DFG Priority Programmes |
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DFG priority programme: "Fundamentals of Electrochemical
Nano-technology"
Head: Prof. U. Stimming (Munich Technical University, Chair of Energy Process Engineering) Sub-project: Scanning Probe Microscope Manipulation
and Characterisation of Electrocatalytic Centres The aim of the project is to study electrocatalytic reactions on individual reactive centres with dimensions in the nanometre range. This is carried out using an instrument we are currently developing which combines the operation of a scanning tunneling microscope in an electrolyte environment (ECSTM) and a scanning electrochemical microscope (SECM) quasi-simultaneously. This device should enable local reactivity information to be assigned to individual topographical features. The model systems to be investigated using this instrument are based on ordered alkane thiol layers on gold surfaces in which shortcomings are induced by means of co-adsorption, sequential occupation, or the STM peak. These defects are to be intensified using metal precipitation. Depending on the type and size of the precipitated metal clusters, structures with differing reactivity occur. Some of the clusters produced in this manner are to be dissolved again by means of oxidation agents produced on the SECM probe. Individual catalytic centres are to be prepared by combining these strategies. They are then to be characterised with STM in terms of their topography and with SECM with respect to their reactivity. Period of funding: 29 September 1997 - 29 September 2001
DFG priority programme: "Structure Gradients in Crystals" Sub-project: Modelling of diffusion-induced segregations
in structure gradients Since 1 October 1998 |
Leipzig-Halle-Jena Research Collaboration |
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Leipzig-Halle-Jena research collaboration Co-operation and complementarity in research and methodological equipment in the field of mineralogy in higher education |
BMBF Interdisciplinary Project |
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BMBF interdisciplinary project: "Instrumentation for X-ray
Fluorescence Spectroscopy with Synchrotron Radiation"
Co-ordinator: Prof. R. Szargan (Wilhelm Ostwald Institute of Physical and Theoretical Chemistry) Prof. R. Szargan, Prof. T. Chassé This project (for which funding has been granted) covers the instrumentation for X-ray emission spectroscopy with angle-resolved and energetically variable excitation and angle-resolved registration, which in combination with a device for recording X-ray absorption spectra and a preparation chamber is designed to open up new applications for intensive X-raying using a third-generation synchrotron source such as BESSY II. The advantages of angle-resolved and polarisation-resolved X-ray emission spectra (element-, edge- and symmetry-specific as well as resonant excitation and an impressively large emersion depth) are to be used by the co-operating users of the participating university institutes (Berlin, Dresden, Leipzig, Würzburg) as well as research establishments of the Max Planck and Leibniz Societies to investigate characteristic phenomena during resonant photoemission and to determine local partial state densities and orbital symmetries. The aim of the work is to produce new types of information on the geometrical and electronic structure of highly ordered ultra-thin layers on metal and semiconductor substrates, on the interface structure of buried layers in semiconductor material, and the electron structure of highly correlated materials. |
Summary |
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The research findings achieved in 1999 have been published in technical journals (see list of scientific publications), summarised in theses (two Habilitation theses, and 47 doctoral theses; see list of dissertations), and presented at congresses, symposia and colloquia. For more detailed information, please see the 1999 Annual Report of the Faculty of Chemistry and Mineralogy. |
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Research Report 1999 | |||||
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