Abstract
[Display omitted]
•Resonance Raman spectra psittacofulvins were measured.•Evidence for a long psittacofulvin is presented.•The frequency dispersion is interpreted within the effective conjugation model.
Spectroscopic studies into the identification and characterisation of psittacofulvins were performed using resonance Raman spectroscopy. It was confirmed that red colour regions display Raman band wavenumber shifts with excitation wavelength, whereas yellow regions do not. There was, however, one yellow region (Calyptorhynchus banksii) that did display wavenumber shifting with excitation wavelength. The data in Raman band wavenumber shifting is observed may be interpreted as probing sample volumes in which a number of dyes of differing length are present in which comparative resonance Raman signals select out the dyes to differing extents depending on their absorption profile, structurally changes between the ground and excited state and the Raman scattering of particular modes. The observed spectral features suggest the presence of a psittacofulvin with greater conjugation than has been reported previously.