Abstract:We show that the overall permutation symmetry (OPS) for the nonresonant susceptibility arises naturally as a consequence of time-reversal symmetry (TRS). Moreover, we obtain the generalized OPS for the resonant susceptibility from the point of view of TRS. PACS. 32.80.Wr â Other multiphoton processes. PACS. 42.50.Ct â Quantum description of interaction of light and matter; related experiments. PACS. 11.30.Er â Charge conjugation, parity, time reversal, and other discrete symmetries.