Microwave Spectrum, Structure, and Dipole Moment ofshyphen;transAcrolein

摘要

The microwave spectrum of acrolein has been studied in the 19ndash;37 kmc region. A series ofRhyphen;type transitions was identified for the ground and three excited torsional states of theshyphen;transisomer and these spectra were successfully fitted in the rigid rotor approximation. Using the ground state moments and additional electron diffraction data a reasonable though not unique structure has been obtained. The torsional frequency was found to be 200plusmn;50 cmmdash;1from relative intensity measurements, and a lower limit of about 2300 cal was estimated for the barrier hinderingtranshyphen;cisconversion. The dipole moment for the ground state was found to be 3.11plusmn;0.04d,oriented about 14deg; from the carbonyl group. The results obtained and the absence of a strongshyphen;cisspectrum establish theshyphen;transisomer as the predominant form.