LAUSR

For the fluorescence measurement, the detailed study of the photophysical and hydrochemical processes had always been ignored. To address these issues, we derived a path equation, which is a probabilistic combination of fluorescence excitation mechanism and the absorption of excitation and emission intensity. Based on the equation, a characteristic parameter, fluorescence yield index (FYI), was deduced. The FYI is related to the light propagation paths and is well suited for physical modeling. Fluorescence emission spectra have been measured from two diverse crude oils by measuring the exciting light. The FYI of samples accurately described the sum of fluorescence yield of the measurement point, and can feedback the best experimental concentration of crude oils. For the same concentration, we can use the FYI to distinguish the different kinds of oils. The theoretical and experimental analyses verify that the path equation and FYI are the efficient way to physically model light–medium interactions.