THE EQUILIBRIUM STRUCTURE OF MONOFLUOROACETYLENE

The equilibrium rotational constants B(e) of HCCF and DCCF have been d etermined from the ground state rotational constants B0, by determinin g the alpha(r) constants for all five fundamentals from the high-resol ution vibration-rotation spectrum making appropriate corrections for t he effects of Fermi resonance. By combination with results from the C- 13 isotopomers and the recent ab initio calculations by Botschwina et al. (Chem. Phys. Lett., 209 (1993) 117), the equilibrium structure is deduced to be: r(e)(CH) = 1.0555 (15) angstrom, r(e)(CC) = 1.1955 (8) angstrom and r(e)(CF) = 1.2781 (8) angstrom