High Resolution Measurements of Hyperfine Structure in the Rotational Spectrum of CH3NC

Abstract

A molecular beam maser spectrometer with separated oscillating fields was used to make very high resolution measurements of hyperfine structure on the $\text{J=1→ 0}$ rotational transition in CH₃NC. Electric and magnetic interaction strengths obtained from analysis of the spectrum are: the nitrogen quadrupole coupling $\text{eqQ=489.4± 0.4\hspace{0.17em}}\mathrm{kHz}$ , the nitrogen spin‐rotation $C_{\mathrm{N}}\text{=1.73± 0.08\hspace{0.17em}}\mathrm{kHz}$ , the hydrogen spin‐rotation $C_{\mathrm{H}}\text{=−0.24± 0.08\hspace{0.17em}}\mathrm{kHz}$ , and the hydrogen‐hydrogen spin‐spin $D_{\mathrm{HH}}\text{=19.5± 0.4\hspace{0.17em}}\mathrm{kHz}$ .