Beam maser spectroscopy on CD3CN

Abstract

The J=1→0 rotational transitions of CD₃CN were measured using a two‐cavity molecular beam maser spectrometer. This spectrometer employs the Ramsey method of separated oscillating fields to obtain very high resolutions and allows precise measurements of the hyperfine structure splittings. The nitrogen quadrupole coupling constant is eq_aaQ(N)=−4229.2±0.6 kHz and the deuterium quadrupole constant is eq_aaQ(D)=−55.1±0.4 kHz. Assuming cylinderical symmetry about the C–D bond axis we obtain the C–D bond‐axis deuterium quadrupole coupling strength of eq_zzQ(D)=169.6±4.5 kHz. The b‐axis rotational constant, and nitrogen and deuterium spin‐rotation interaction strengths are also reported.