Laboratory millimeter wave spectrum of N-methylhydroxylamine

Abstract

The pure rotational spectrum of N-methylhydroxylamine (CH3NHOH), a potential candidate in the interstellar medium, has been studied in the millimeter-wave region up to 360GHz. The molecule was liberated from its hydrochloride salt and the ground and six lowest excited vibrational states of the most stable trans conformation as well as the 13C isotopologue in natural abundance have been measured and analyzed. From the observed ground state A–E splittings, a barrier hindering the methyl internal rotation V3=1245.8 (46) cm−1 has been derived. The sub-Doppler Lamb-dip technique has been employed to resolve the 14N hyperfine structure of strong transitions. The spectroscopic constants reported in the present study should constitute a solid set of laboratory data to support future searches of N-methylhydroxylamine in the interstellar medium.