The rotational spectrum of cyclobutadiene iron tricarbonyl was measured using a Flygare-Balle-type microwave spectrometer. Twenty a-dipole transitions were measured in the 5-16 GHz range for this prolate symmetric-top molecule. A least-squares fit of the data to a distortable symmetric top Hamiltonian yielded B = 961.9856(8) MHz, DJ = 0.184(8) kHz, DJK = 1.20(3) kHz. These results indicate that the vibrationally averaged structure of the cyclobutadiene ring is square and perpendicular to the a-molecular axis.
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics
- Physical and Theoretical Chemistry