Knowledge Bank

The far infrared spectra of $FCH2CXO$ where $X=F,Cl$, and Br have been recorded, and the asymmetric torsional vibration has been identified for two conformers for each molecule. Each torsional transition shows a number of hot bands on the low frequency side of the fundamental. These transitions have been utilized to obtain the potential functions from which the barriers to internal rotation and the energy differences between the conformers have been obtained. Experimental values of the $\Delta H$ have also been obtained from the Raman spectra of each molecule as a function of temperature. These results will be compared to those obtained from ab initio calculations.