Characterization of silicon-carbon clusters by infrared laser spectroscopy. The v1 band of SiC4

The v1 fundamental vibration of linear SiC4 has been observed by infrared diode laser spectroscopy of a supersonic cluster beam. Twenty-four rovibrational transitions were measured in the spectral region of 2094.6 to 2097.1 cm−1, the rotational temperature was 10 K. A combined least-squares fit of these transitions with previously reported microwave data yielded the following molecular constants: v1 = 2095.45806(37) cm−1, B″ = 0.051161131(52) cm−1, and B′ = 0.0509157(96) cm−1. These results are compared to vibrational spectroscopy measurements of SiC4 trapped in a solid Ar matrix and to ab initio calculations.