02.03.2018 - An Intuitive Demonstration of First Order Kinetics for the Lecture Hall

Many time dependent phenomena like radioactive decays and a plethora of chemical reactions obey first order kinetics. It is, thus, part of all chemistry and physics curricula. An intuitive introduction to the topic is described in our recent contribution for the Journal of Chemical Education. The lecture hall demonstration outlined therein relies on capillary flow and digital data acquisition. With a simple set-up a first order process can literally be seen. Read more in undefinedL. Festersen, P. Gilch, A. Reiffers, R. Mundt, J. Chem. Educ. (2018).

19.02.2018 - Scholarship for Janina Diekmann

Jürgen Manchot Stiftung

Our PhD student Janina Diekmann was awarded a scholarship by the undefinedJürgen Manchot Stiftung. This institution will support her research on light induced DNA damage for two years.

10.07.2017 - A New Approach towards More Efficient OLEDs?

Organic light emitting diodes (OLEDs) are nowadays widespread in display and illumination technology. All OLEDs contain molecular emitters to facilitate the transformation of electricity into light. These emitters are often based on precious metals like iridium or require cumbersome synthesis. In a recent paper published together with undefinedAndrew Monkman’s group at Durham university we give experimental evidence that some low cost aromatic carbonyls have a very large potential for this purpose. Read more: undefinedTriplet Harvesting with a Simple Aromatic Carbonyl.

09.09.2016 - Femtosecond Spectroscopy on a Major Component of Bacterial Spores

Bacterial spores are very resistant towards environmental hazards, in particular UV radiation. The role of calcium dipicolinate – a major component of theses spores – in this UV resistance has been debated for decades. In a undefinedrecent publication we provide a comprehensive characterization of the compound by time resolved spectroscopy. Our results show that photo-excited calcium dipicolinate may interact with the DNA of spores. It remains to be seen whether this interaction is beneficial or detrimental to spores.

07.06.2016 - Poster prize for Jakob Nixdorf

Recently, our PhD student Jakob Nixdorf attended the 4th international undefinedRamanFest in Berlin, organized by HORIBA Scientific, in partnership with the Humboldt University of Berlin. We are very happy that his presentation “Femtosecond stimulated Raman microscopy (FSRM) with a 10 kHz acquisition rate” was awarded with one of the poster prizes.

12.04.2016 - Journal Cover

Ortho-di-substitution of benzenes provides the opportunity to study interactions between diverse functional groups in a defined environment. The substituents are forced to distances which allow chemical reactions to occur. In a undefinedFeature Article in the Journal of Photochemistry and Photobiology A, we focus on photoreactive compounds containing nitro and carbonyl groups, which we have been studying for several years. The complex electronic structure of these molecules results in a rich photochemistry on the femto- and picosecond timescale. A combination of femtosecond spectroscopic techniques and quantum chemical calculations shows that all compounds investigated undergo hydrogen transfers via both, singlet and triplet channels. The experiments enabled us to elucidate the mechanisms of prominent photoreactions as the ones of ortho-nitrobenzaldehyde or of nitrobenzene derived photolabile protecting groups.

25.02.2016 - Thioxanthone in apolar solvents: ultrafast internal conversion precedes fast intersystem crossing

Long-lived triplet states of organic molecules play a key role in their photoreactivity. Thus, the principles underlying the population of triplet states are of great importance for photochemistry. In relation with organic photovoltaics and organic light emitting diodes they are presently intensively studied. We have looked at the population of the triplet state of thioxanthone (TX) in cyclohexane via intersystem crossing (ISC). TX is prototypical for a class of molecules undergoing efficient ISC. By means of undefinedfemtosecond spectroscopy the time constant for ISC was determined to be 4 ps. This is in excellent agreement with the value (6 ps) computed by the undefinedMarian group co-authoring the paper. This and undefinedprevious contributions highlight the influence of the solvent on ISC processes. Whereas in protic solvents the initial process is an ISC one here undefinedultrafast internal conversion (IC) precedes the fast ISC.

Verantwortlich für den Inhalt: E-Mail sendenProf. Dr. Peter Gilch