Microwave spectrum, rs structure, dipole moment, and nuclear quadrupole coupling constant tensor of ethyl lodide

Abstract

Microwave spectra of ethyl iodide and its six isotopic species have been measured. A least-squares analysis of the observed frequencies gave rotational, quartic centrifugal distortion constants and the components of the nuclear quadrupole coupling constant tensor for all the seven isotopic species. The r s structure has been well established from the moments of inertia calculated from the observed rotational constants. The observed nuclear quadrupole coupling constant tensor in the inertial principal axes system could be transformed into that in its own principal axes system which gave the following conclusions. The tensor is roughly cylindrically symmetric around the z axis which is slightly deviated by about 56′ from the CI internuclear line. From the Stark effect measurements of several low J transitions for the three isotopic species, the dipole moments have been determined. For the normal species, μ a = 1.884(3) D, μ b = 0.598(10) D, and μ total = 1.976(5) D and the dipole moment makes an angle of 2°9′ with the CI bond.