Microwave field effect on the fluorescence of (COF)2 excited to the 000 band of the أ1Au state

The effect of a microwave field (λMW = 3 cm) in the presence of an external magnetic field has been observed on the fluorescence of (COF)2 excited to the vibrationless level of the Ã1Au state. The microwave field results in additional resonance quenching of the (COF)2 fluorescence in the 0.33 T region. This effect corresponds to the optically detected EPR spectrum of the excited vibrational levels of the ã3Au state and it proves that magnetic quenching of the (COF)2 fluorescence is realized by the indirect mechanism.