LASER SPRECTROSCOPIC STUDIES OF $Si_{3}C$ AND $Si_{3}$

$^{1}$ J. Fulara, P. Freivogel, M. Grutter, and J. P. Maier, J. Phys. Chem. 100, 18042 (1996).Author Institution: Harvard-Smithsonian Center for Astrophysics; Division of Engineering Applied Sciences, Harvard University; Institute for Theoretical Chemistry, Department of Chemistry and Biochemistry, The University of Texas at AustinLaser experiments to measure the electronic spectra of $Si_{3}C$ and $Si_{3}$ in the gas phase by R2C2PI spectroscopy with Time of Flight Mass Spectrometry will be presented. The strong $\tilde{C}^{1}B_{1} \longrightarrow \tilde{X}^{1}A_{1}$ transition of $Si_{3}C$ is detected at $24933 cm^{-1}$. The complex band profile can be explained as vibrational progressions from at least two modes. Using matrix data from J. Fulara $et al.^{1}$, the $^{1}A_{1} \longrightarrow \tilde{X}^{1}A_{1}$ band of $Si_{3}$ at $18605 cm^{-1}$ has also been observed. The status of the search for the microwave spectrum of $Si_{3}C$ on the basis of recent high level ab initio calculations will be discussed. Both molecules are of astronomical interest because they are structurally similar to the known astronomical $SiC_{2}$ and $SiC_{3}$ species