Knowledge Bank

The vibrational spectra of 2,3-difluoro, 2,3-dichloro and 2,3-dibromobutadiene have been measured with the compounds in the gaseous, liquid and solid states. The spectra can be attributed to a $C2h$ form of the molecule. There is no indication of a non-$C2h$ species. A complete vibrational analysis has been carried out and the results of a preliminary normal coordinate calculation for the series of molecules will be presented.