High-resolution spectroscopy of the 000,201,301 and 311 bands in the A∼1B2-X∼1A1 transition of SiC2

Abstract We present a high-resolution spectroscopic study of the A ∼ 1 B 2 - X ∼ 1 A 1 transition of SiC 2 by laser-induced fluorescence. The gas-phase SiC 2 molecules are produced in a discharge plasma and cooled in a supersonic jet expansion. By employing a home-made single longitudinal mode optical parametric oscillator as the narrow bandwidth laser source, laser excitation spectra have been recorded with a transition frequency accuracy of ∼ 0.004 cm - 1 for the 0 0 0 , 2 0 1 , 3 0 1 and 3 1 1 bands. Rotational analyses of the high-resolution data have yielded accurate spectroscopic constants, including the centrifugal distortion constants, for the upper vibronic states studied here.