Abstract
The dynamic effect concerning small mixing of first-excited state to ground state due to the ligand vibration (which can bring about a twinkling tetrahedral change from compression to elongation) is introduced to calculate the gyromagnetic (g) factors of the second compressed tetragonal molybdenum (V) tetrahedral center in the light-irradiated lead molybdate crystal. The computed results agree well with the observed values, and the large deviation of the observed g// from ge (≈2.0023, the free electron g factor) is therefore interpreted. The outcomes (particularly, the percentage in time for the twinkling tetrahedral change from compression to elongation) are discussed.