The microwave spectrum of 1-chloro-2-methylpropene

The rotational spectrum of 1-chloro-2-methylpropene has been measured with very high resolution using pulsed molecular-beam Fourier transform microwav e (MB-FTMW) spectrometers in the range from 3 to 40 GHz. The analysis yield ed accurate rotational constants, centrifugal distortion constants, the com plete Cl-35 and Cl-37 quadrupole coupling tensors, and the V-3 hindering ba rriers of both methyl rotors. These results supplement and improve previous observations made with waveguide microwave and infrared spectroscopy under considerably lower resolution. Moreover, a potential surface depending on the two angles of internal rotation was calculated using nb initio methods. This enabled us to compare theoretical and experimental potential barriers and to obtain information on higher potential terms and top-top interactio n constants, which were not available from the experimental data alone, (C) 2000 Academic Press.