Laser spectroscopy of the Ã(2)Σ(+)-X̃(2)Πi band system of l-SiC3H.

The Ã(2)Σ(+)-X̃(2)Πi band system of l-SiC3H in the region 14,700-16,300 cm(-1) was re-investigated by laser induced fluorescence (LIF) and fluorescence depletion spectroscopy. Rotational analyses were made for three intense bands 0(0)(0), 4(0)(1), and 6(0)(1)7(0)(1) by observing high-resolution LIF excitation spectra. The determined rotational constants demonstrate that SiC3H is linear in the à state, as is the case in the X̃ state, and the observed band types are consistent with the vibrational assignments. The ν3(″) (C1-C2 stretch) level was identified in a newly observed dispersed fluorescence spectrum from the zero-vibrational level of the à state.