Acetyl Methyl Torsion in N-Ethylacetamide: A Challenge for Microwave Spectroscopy and Quantum Chemistry
Résumé
The gas phase structures and parameters describing the acetyl methyl torsion of N-ethylacetamide were determined with very high accuracy using a combination of molecular beam Fouriertransform microwave spectroscopy and quantum chemical calculations. Conformational studies at the MP2 level of theory yielded four minima on the energy surface. The most energetically favorable conformer, which possesses a C1 symmetry, was experimentally observed and assigned. The torsional barrier of the acetyl methyl group was obtained to be 73.4782(1) cm-1. Due to this rather low barrier, fine splittings up to 4.9 GHz were found in the spectrum. The conformational structure was not only confirmed by the rotational constants but also by the orientation of the internal rotor. The 14N quadrupole hyperfine splittings were analyzed and compared with theoretical calculations.
Origine : Fichiers produits par l'(les) auteur(s)