THE CENTIMETER AND MILLIMETER MICROWAVE-SPECTRA OF BUTADIENE SULFONE AND ALPHA,ALPHA'-D4 BUTADIENE SULFONE

Microwave measurements on the ground and first eight excited states of the ring-puckering vibration of butadiene sulfone have been extended to millimeter wavelengths. The microwave spectra of the same vibrational states of α,α′-D4 butadiene sulfone have been observed. For both isotopomers the Coriolis interaction between the v = 0 and v = 1 states has been analyzed to give the energy separation between these two states. These data and the variation of the rotational constants have been used to derive reduced potential functions for the ring-puckering vibration. The barrier to ring inversion is 49(2) cm-1 for butadiene sulfone and 44(2) cm-1 for the α,α′-D4 isotopomer. The ring-puckering vibrational dependence of the quartic centrifugal distortion constants, including a small dependence of ΔJ and δJ, has been accounted for. © 1991.