Fluorescence scattering under the Stokes–Mueller formalism determines the orientational distribution of fluorophores and the nature of optically active biological proteins

Abstract In the current paper, we represent intrinsic fluorescence anisotropies as four-dimensional normalized Stokes vectors defined by the maximum excitation and emission in the fluorescence process with respect to linear, linear-45 and circular polarizations of light. Depending upon the transition moments for absorption/excitation and emission of fluorophores, eight types of these Stokes vectors can be realized from the Mueller fluorescence matrix of the system. These Stokes vectors probe the orientational distribution of fluorophores and predict the nature of optically active biological proteins, whether laevorotatory or dextrorotatory. The orthogonality relation between the Stokes vectors corresponding to the excitation and emission processes of fluorescence connects the molecular ground and excited states of biological and non-biological systems.