Abstract The microwave spectra of three isotopic species of methyl fluoroformate, CD 3 OCFO, CD 2 HOCFO and CH 3 18 OCFO have been measured and assigned. A barrier to internal rotation of 372±2 cm− 1 has been obtained for three symmetric internal rotor species from internal rotation analyses. The rotational constants from five isotopic species have been used to determine an r 0 structure for the s-trans conformer (methyl group trans to fluorine) ...
