Study of carbon chains, absorbance, and large amplitudes (SCALA)

• Applicant: Professor Dr. Hans Bürger
• Subject Area: Physical Chemistry of Molecules, Liquids and Interfaces, Biophysical Chemistry
• Term: from 2002 to 2008
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 5380654

The project is dedicated to the study of reactive molecules with two main goals: On the one hand the improvement of the knowledge of their molecular structures and potential energy surfaces and on the other hand the application of the results to the detection and quantitative retrieval of these species in the earth´s atmosphere and in the interstellar medium. To achieve these tasks, laboratory syntheses, recording of rotational and rovibrational spectra, analyses by means of appropriate Hamiltonians and line intensity models are required. Such broad and deep expertise is not available in any single laboratory but is created by the present project. The three proposing teams, which have successfully collaborated in the past, belong to chemistry and physics and hereby evidence the interdisciplinary character of the project. The individual expertise of the teams is geared in three main tasks which are at the borderlines of synthetic chemistry, molecular physics and applications (planetary atmospheres, astrophysics): An extensive spectroscopic study of different monoisotopic species of the unstable F2BOH molecule both to determine accurately its structure and understand its large amplitude motion. The results will be compared to those already obtained for the isovalent HONO2 molecule and possibly to the still hypothetical fluoroformic acid. The study of the carbon-chain molecule NCCCCN which is likely to be present in Titan. This centrosymmetric molecule does not possess indeed a pure rotation spectrum and its detection by sub-millimeterwave spectroscopy will be possible only through the observation of rovibrational transitions. The accurate measurement of absolute line intensities for two molecules of great atmospheric relevance, namely O3 and HOBr. The first one requires line intensities to be known to better than ~1% (today the accuracy is not better than 4%) whereas no line intensities at all are available for HOBr owing to its fast self-depletion.

• DFG Programme: Research Grants
• International Connection: France
• Participating Persons: Jean Demaison, Ph.D.; Jean-Marie Flaud