Laser-induced fluorescence detection of the elusive SiCF free radical

Gretchen Rothschopf; Tony C Smith; Dennis J Clouthier

doi:10.1063/1.5040473

Laser-induced fluorescence detection of the elusive SiCF free radical

J Chem Phys. 2018 Jul 14;149(2):024301. doi: 10.1063/1.5040473.

Authors

Gretchen Rothschopf¹, Tony C Smith¹, Dennis J Clouthier²

Affiliations

¹ Ideal Vacuum Products, LLC, 5910 Midway Park Blvd. NE, Albuquerque, New Mexico 87109, USA.
² Department of Chemistry, University of Kentucky, Lexington, Kentucky 40506-0055, USA.

PMID: 30007371
DOI: 10.1063/1.5040473

Abstract

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∑+2-X̃∏2 band system in the 610 - 550 nm region was recorded and the ∏3/22 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=1.6921Å 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.