Deuterium Quadrupole Coupling in Formyl Fluoride

The 1₀₁–0₀₀ rotational transition in HFCO and DFCO was recorded with a beam maser spectrometer. Hyperfine structure due to the deuterium quadrupole coupling was observed for DFCO. Analysis of the spectrum yielded the deuterium quadrupole coupling strength along the D–C bond direction of $\text{eqQ\hspace{0.17em}=\hspace{0.17em}205.\hspace{0.17em}±\hspace{0.17em}4.}\mathrm{kHz}$ . This rotational transition had not been reported previously for DFCO. A comparison of deuterium quadrupole coupling strengths with force constants along the H–C bond is made according to the theory of Salem.