Nuclear Quadrupole Effects in the Microwave Spectrum and Dipole Moment of Aniline

Abstract

The quadrupole hyperfine structure was resolved and analyzed for the vibrationally-ground state of the NH2 species. The quadrupole coupling constants are: χaa=2.34, χbb=1.86, and χcc=−4.20 MHz. The rotational constants obtained from the quadrupole corrected frequencies are as follows: A=5617.67, B=2593.88, and C=1777.04 MHz. The rotational constants of the ND2 species in the vibrationally-ground state were also determined. By the use of the moments of inertia of both species, the non-planarity of this molecule was ascertained. The dipole moments of the NH2 and the ND2 species were determined to be 1.15±0.02 D and 1.13±0.01 D respectively.