Molecules in the excited states
C. Daniel, E. Gindensperger, R. Marquardt
The research work in the field of excited states comprises to some extent methodological developments aimed at understanding the motion of highly excited molecules. This work should also help to test the latest developments in electronic structure calculation devoted to the treatment of highly excited electronic and vibrational levels of polyatomic molecules, including singular portions of the potential energy surfaces such as conical intersections. One of the interests focuses on the excited electronic levels of coordination compounds. Work is also carried out regarding the high resolution ro-vibrational spectroscopy of tri- to penta-atomic molecules upon consideration of all degrees of freedom. The goal is to produce accurate theoretical spectroscopic tools to analyse the photochemistry, photophysics and the intramolecular kinetics related to excites states.
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The theory is applied to the study of mono and bimetallic transition metal complexes, mid-sized organometallic compounds and ranges down to the study of high vibrational overtones of isolated molecules in the gas phase, which makes the bridge to the “molecular quantum dynamics” topic of the laboratory's research. The figure shows the process of photoinduced ammonia stereomutation. The study invokes quite a large number of vibrationally excited states to up to the 2nd overtone of the NH stretching motion and allows to answer the question: “Is it possible to generate planar ammonia by exciting the NH stretching vibration?” The specificity of the work developed in the laboratory is to use the methods at the current limit of both theoretical and computational possibilities in order to investigate particular spectroscopic, photophysical and photochemical molecular properties, which might turn out to find potential application in several physical and chemical domains such as material sciences, biology, lasers, catalysis, or polymerization kinetics, just to mention a few examples. |
