Reactions of photogenerated fluorine atoms with contaminant molecules trapped in solid argon 5.~* EPR spectroscopy of FC_(60)~(centre dot) dical in solid argon

摘要

Reactions of photogenerated fluorine atoms with C60 fullerene molecules isolated in solid argon were studied by EPR spectroscopy in the temperature range from 15 to 25 K. Highly resolved anisotropic EPR spectrum of the FC_(60)~(centre dot) radical was obtained for the first time. The spectrum is characterized by low anisotropy of the g-tensor and by axialfy symmetric HFC tensor on ~(19)F nuclei. The parameters of the HFC tensor for ~(19)F magnetic nuclei were determined. The isotropic HFC constant A_(iso) equals 202.8 MHz and the anisotropic magnetic dipole-dipole interaction constant A_(dip) equals 51.8 MHz. Quantum chemical calculations of FC_(60)~(centre dot) radical showed that the PBE1/A22m method (PBE1 functional and the correlation triple-zeta basis sets augmented with polarization functions on inner atomic shells) provides good agreement between the theoretical magnetic parameters and experimental data. Specific features of the spin density distribution in the FC_(60)~(centre dot) radical are discussed.