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JENS-UWE GRABOW, EIKE HENTROP AND DIETER H. SUTTER, Chistian-Albrechts-Universiät, Institut für Physikalische Chemie, Abteilung Chemische Physik, Olshausenstrasse 40, D-24098 Kiel, Germany.
We present an investigation of the deuterium nuclear quadrupole coupling in a series of carbonic acids R-COOH: Among those, the acids with the groups R = CH3 and R = CF3 are two extreme cases for substituent effects on the charge distribution at the carboxyl group. The deuterium nuclear quadrupole coupling serves as a sensitive probe for the electric field gradient at the location of the acidic proton.
The rotational spectra and the quadrupole coupling hyperfine structures of several R-substituted carbonic acids R-COO2H in the range of 6 to 26.5 GHz are reported.
Quantum chemical calculations were performed to determine the nuclear quadrupole coupling tensor of 2H. The analysis of the nuclear quadrupole coupling in the rotational spectra provided experimental information on the tensors.