An electron spin resonance investigation of the 12C11B12C, 12C11B13C, and 13C11B13C radicals in neon, argon, and krypton matrices: Comparison with ab initio calculations

The 11 electron CBC radical has been generated by the pulsed laser vaporization of elemental carbon–boron mixtures and trapped in neon, argon and krypton matrices for detailed electron spin resonance (ESR) studies. Extensive comparisons of the experimental nuclear hyperfine A tenors for carbon and boron were made with a variety of ab initio computational results that involved different levels of theory and basis sets. These new ESR results agree with recent vibrational studies of CBC that show it to have a nonlinear symmetric geometry with a 2A1 electronic ground state. These ESR results provide a description of the singly occupied molecular orbital. The spin density resides primarily on boron in 2s and 2pz orbitals, however a complete resolution of the 13C hyperfine structure does show that approximately 20% resides on the carbon atoms.