Theoretical Predictions and Experimental Detection of the SiC Molecule

The 0-0 band of the d¹Σ⁺-b¹Π electronic transition of SiC was detected near 6100 cm^-1. The SiC molecule was observed by high-resolution Fourier-transform emission spectroscopy from a composite-wall hollow cathode. Ab initio quantum chemical calculations confirm the identity of the carrier of the spectrum as SiC and the d¹Σ⁺-b¹Π assignment. Combination of the observed r₀ for SiC b¹Π with theoretical shifts in bond lengths from b¹Π to X³Π gives the astrophysically important bond lengths r₀=1.723 {} and rₑ=1.719 {} for X³Π to an estimated accuracy of 0.001 {}.