MICROWAVE-SPECTRUM OF ETHYL FLUORIDE AND STRUCTURE OF CH3MH2X TYPE MOLECULES

Microwave spectra of ethyl fluoride and its 19 isotopic species were measured to establish the rs structure. Stark-effect measurements of several low-J transitions were carried out for the normal and CD3CH2F species. The molecular structures, dipole moments, and nuclear quadrupole coupling constant tensors of CH3MH2X type molecules (M = C, Si, Ge, X=F, Cl, Br, I) were compared. For molecules whose structures had been obtained by different choices of assumptions, the rs coordinate values were re-calculated from the reported data with assumptions similar to those of the present analysis. The systematic shifts of the structural parameter values and of the directions of dipole moments, and the principal axes of the nuclear quadrupole coupling constant tensors, are discussed. © 1990.