Raman spectra of asymmetric top molecules. Part 1.—The pure rotational spectrum of ethylene

From an investigation of the rotational Raman spectrum of ethylene, single transitions were assigned which allowed the determination of all three rotational constants: A0= 4.8666± 0.0040 cm–1, B0= 1.00076± 0.00013 cm–1, C0= 0.828 48± 0.000 16 cm–1.The spectrum was also computer simulated using an asymmetric rotor programme and, from a comparison of observed and calculated spectra, values were determined for the principal polarisabilities of the molecule: αzz= 5.40 Å3, αxx= 3.86 Å3, αyy= 3.40 Å3.