15min:

J. DUDEK, M. C. MCCARTHY AND P. THADDEUS, Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, and Division of Engineering Applied Sciences, Harvard University, 29 Oxford Street, Cambridge, MA 02138; J. F. STANTON, Institute for Theoretical Chemistry, Department of Chemistry and Biochemistry, The University of Texas at Austin, Austin, Texas 78712.

Laser experiments to measure the electronic spectra of Si₃C and Si₃ in the gas phase by R2C2PI spectroscopy with Time of Flight Mass Spectrometry will be presented. The strong C¹B₁ X¹A₁ transition of Si₃C 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 ¹A₁ X¹A₁ band of Si₃ at 18605 cm^-1 has also been observed. The status of the search for the microwave spectrum of Si₃C 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 SiC₂ and SiC₃ species.

¹ J. Fulara, P. Freivogel, M. Grutter, and J. P. Maier, J. Phys. Chem. 100, 18042 (1996).