Modeling of the population dynamics of the states of a three-level molecule in the field of a monochromatic light wave

The formalism and the results of modeling the population dynamics of the states of a three-level model molecule by using the optical Bloch equations are compared with the formalism and results of modeling the population dynamics of the states of the molecule–radiation field system by means of quantum electrodynamics. Examples of significant differences between the results of application of these approaches regarding the behavior of the time dependences of the populations of the states of the molecule, the values of the quantum yield of the photoreaction or the intensity of Rayleigh and resonance Raman scattering are given. These differences are the greater, the higher the rate of the radiative decay of the resonantly excited state with the transition of the molecule to the ground state as compared to the rate of the decay of this state with the transition of the molecule to the third molecule (undecaying) state.