Submillimeterwave Spectroscopy of and Interstellar Search for Nitrosomethane: CH3NO

Abstract

New measurements of nitrosomethane (CH _3 NO), a formamide isomer, were done up to 660 GHz. The molecule exhibits internal rotation motion from the CH _3 group, and therefore the analysis with a dedicated rho-axis method code, RAM36, was used. A total of 2035 lines for v _t = 0 and 1 states of A and E symmetries were fitted with an rms deviation of 41.1 kHz, with the maximum quantum numbers values J = 30 and K _a = 15. Using these new data, CH _3 NO was searched in the cold dark cloud Taurus Molecular Cloud 1 as well as the high mass star-forming regions Sgr B2(N) and NGC 6334I. CH _3 NO was not observed in any of the sources, 3 σ column density upper limits were determined, and we discuss the implications for the chemistry of CH _3 NO in the interstellar medium. The accurate spectroscopic prediction of its spectra provided in this work will allow astronomers to continue the search of CH _3 NO in other interstellar sources.

Keywords

• Astrochemistry