Electron paramagnetic resonance of Li–CO2 complexes in a CO2 matrix at 77 K

Li–CO2 complexes have been obtained by the condensation of a Li atomic beam in a CO2 matrix at 77 K. Electron paramagnetic resonance measurements show that the Li 2s electron is strongly localized on a CO2 molecule and consequently CO−2 molecular ions are nearly formed. The g tensor and the C13 and O17 hyperfine tensors are characterized by two principal values. This axial symetry can be explained by a rotation of the CO−2 ions around the molecular axis O–O.