The SiCF free radical has been spectroscopically identified for the first time. The radical was produced in an electric discharge jet using CF3Si(CH3)3 or CF3SiH3 vapor in high pressure argon as the precursor. The laser-induced fluorescence spectrum of the Ã 2Σ+ − X̃ 2Π band system in the 610 − 550 nm region was recorded and the 2Π3/2 spin component of the 0—0 band was studied at high resolution. Rotational analysis gave the B values for the combining states, and by fixing the CF bond lengths at ab initio values we obtained r″(Si–C) = 1.692(1)Å and r′(Si–C) = 1.594(1)Å. The bond lengths correspond to a silicon-carbon double bond in the ground state and an unusual Si−C triple bond in the excited state. Single vibronic level emission spectra yielded the ground state bending and stretching energy levels. These were fitted to a Renner-Teller model that included spin-orbit and limited vibrational anharmonicity effects.
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This research was funded by Ideal Vacuum Products.
Rothschopf, Gretchen; Smith, Tony C.; and Clouthier, Dennis J., "Laser-Induced Fluorescence Detection of the Elusive SiCF Free Radical" (2018). Chemistry Faculty Publications. 130.