The Microwave Spectrum of Ethyl Fluoride

Abstract

The microwave spectrum of ethyl fluoride has been investigated in the region from 17 to 38 kMc. The values of the rotational constants of the molecule obtained from the analysis of the spectrum are: A = 36070.30±0.10 Mc, B = 9364.54±0.10 Mc, and C = 8199.74±0.10 Mc. The following structural parameters have been fitted to these rotational constants: r_CH = 1.091A, r_CC = 1.540A, r_CF = 1.375A, and tetrahedral bond angles. The dipole moment components along the principle axes of the molecule are μ_A = 1.69D and μ_B = 1.00D; the total dipole moment, μ = 1.96±0.03D, is oriented at an angle of 64° with respect to the C–C bond axis, or approximately 7° from the C–F bond axis. The barrier height for internal rotation is 1490±50 cm^—1 (4260 cal/mole).