Low barrier methyl rotation in 3-pentyn-1-ol as observed by microwave spectroscopy |
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| Authors: | Konrad Eibl Raphaela Kannengießer Wolfgang Stahl Isabelle Kleiner |
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| Institution: | 1. Institute of Physical Chemistry, RWTH Aachen University, Aachen, Germany;2. Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA), CNRS UMR 7583, Université Paris-Est Créteil and Université Paris Diderot, Créteil cedex, France;3. Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA), CNRS UMR 7583, Université Paris-Est Créteil and Université Paris Diderot, Créteil cedex, France |
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| Abstract: | ABSTRACTThe rotational spectrum of 3-pentyn-1-ol, CH3?C≡C?CH2CH2OH, was measured using a molecular beam Fourier transform microwave spectrometer operating in the frequency range from 2 to 26.5 GHz. A two-dimensional potential energy surface was calculated at the MP2/6-311++G(d,p) level of theory for a conformational analysis, yielding five conformers. The most stable conformer exhibits C1 symmetry and was assigned in the spectrum by comparison with the results from quantum chemical calculations. The barrier to internal rotation of the propynyl methyl group CH3?C≡C? was found to be only 9.4552(94) cm?1. Molecular parameters and internal rotation parameters could be accurately determined using the program xiam and belgi-C1. The internal rotation barrier was compared with those of other molecules containing a propynyl methyl group. |
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| Keywords: | Propynyl rotational spectroscopy internal rotation large amplitude motion conformation analysis potential energy surface |
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