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Leaf reflectance and transmittance spectra in the 400-800 nm region embody information about multiple photosynthetic and photo-protective pigments which are closely linked to vegetation physiological and ecological functions.However, this information is difficult to obtain because the absorption spectra of different pigments overlap which can mask the contribution of individual pigments to the reflectance spectrum.Consequently, leaf radiative transfer models often incorporate a simplified absorption coefficient which assumes linear contributions of the specific pigment absorptions, but this restricts the retrieval of individual pigment concentrations from leaf spectra by model inversion.Therefore, in order to improve the capabilities for pigment retrieval,this study investigated the feasibility of incorporating individual pigment absorption functions into the absorption coefficient used within a leaf radiative transfer model.This was achieved in three development phases.Firstly, a Gauss-Lorentz function was employed to provide a spectral peak separation capability for characterizing pigment-specific absorption coefficients and transforming the linear leaf absorption coefficient into a non-linear function relationship and thereby avoiding the masking phenomena in model parameter separation.Secondly, a red-shift distance parameter was introduced to describe the relationship between the absorption peak positions of specific pigments in vivo and in an organic solution extract (from which absorption spectra are typically measured).These treatments of the leaf absorption coefficient function enabled the characterization of separable pigment specific absorption coefficients in vivo.Thirdly, a new leaf radiative transfer model (FOLIUM1) was developed to retrieve multiple individual pigment concentrations from 400-800nm spectra of fresh leaves.