Spectroscopic parameters of SiC4

► The interpretation of unidentified lines coming from the new astrophysical laboratories Herschel and ALMA will require the knowledge of many spectroscopic properties of uncharacterized molecules, given an important attention to the chemistry of silicon. ► In the extraterrestrial chemistry, Si plays an important role because it has a significant cosmic abundance and takes part of near a 10% of the detected molecules in astrophysical objects. Many molecular species SiO, SiS, SiN, SiH2, and several silicon bearing molecules (CnSi type) are listed as discovered species and many are expected to be discovered. ► MW and FIR properties of linear-SiC4 are derived from RCCSD(T) and RCCSD(T)-F12 ab initio methods and second order perturbation.