Ethyl methyl sulfide rotational spectroscopy

In order to understand the chemical behaviour of the ISM and specific cases like the missing sulfur reservoir, a detailed chemical molecular composition in the ISM must be mapped out. Our goal is the investigation of the rotational spectrum of ethyl methyl sulfide, CH_3_CH_2_SCH_3_, which seems to be a potential candidate to be observed in the ISM since the simpler analogs, CH_3_SH and CH_3_CH_2_SH, have been already detected.

Rotational spectrum of ethyl methyl sulfide has been observed before, but its experimental rotational parameters are not precise enough to allow its detection in the ISM. The rotational spectrum of ethyl methyl sulfide in the frequency range 72-116.5GHz was measured using a broadband millimeter-wave spectrometer based on radio astronomy receivers with fast Fourier transform backends. The spectral searches and identification of the vibrational excited states of ethyl methyl sulfide was supported by high-level ab initio calculations on the harmonic and anharmonic force fields.