Electron Spin Resonance Absorption Spectrum of CO2− Molecule Ions Associated with F− Ions in Single-Crystal Calcite

Abstract

Single crystals of calcite subjected to $\gamma$ irradiation exhibit a number of paramagnetic defect centers. One of these has been identified as the CO₂⁻ molecule ion which is in close association with an F⁻ impurity ion. An analysis of the ESR superhyperfine structure due to the fluorine nucleus suggests that for 3.3% of the time, negative charge is transferred from the F⁻ ion to the CO₂⁻ molecule ion. This transfer of charge creates the diamagnetic CO₂²⁻ molecule ion and atomic fluorine whose electron configuration is approximately 90% ${\text{(2s}}^2{\text{2p}}^5)$ and 10% ${\text{(2s2p}}^6)$ . The effective magnetic field at the fluorine nucleus due to core polarization and $\text{2s}$ contact is calculated to be 21 kOe.