Laser spectroscopy of the Ã2Σ+−X̃2Πi band system of l -SiC3H

The Ã2Σ+−X̃2Πi 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 000, 401, and 601701 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.