Precise dipole moment and quadrupole coupling constants of benzonitrile

TL;DR

This study uses microwave spectroscopy to precisely measure the dipole moment and quadrupole coupling constants of benzonitrile, providing detailed molecular property data.

Contribution

It offers the first accurate experimental determination of benzonitrile's dipole moment and nuclear quadrupole coupling constants using hyperfine-resolved microwave spectroscopy.

Findings

Dipole moment of benzonitrile is 4.5152 D.

Accurate rotational and quadrupole constants were obtained.

Hyperfine-resolved microwave transitions were analyzed.

Abstract

We have performed Fourier transform microwave spectroscopy of benzonitrile, without and with applied electric fields. From the field-free hyperfine-resolved microwave transitions we simultaneously derive accurate values for the rotational constants, centrifugal distortion constants, and nitrogen nuclear quadrupole coupling constants of benzonitrile. By measuring the Stark shift of selected hyperfine transitions the electric dipole moment of benzonitrile is determined to $\mu=\mu_a=4.5152 (68)$ D.