Experimental and theoretical studies of resonance Raman scattering: Temperature effects in β-carotene

The Raman excitation profile of β-carotene in isopentane solution has been measured at 118 and 298 K using stilbene dye laser excitation as well as argon laser lines. This data as well as absorption data have been analyzed by using a model which includes the conventional multimode and band shape function. With this model, the parameters of normal coordinate displacement and damping constant, and the effect of temperature and band shape function on the width and peak position can be explored. Using the same set of parameters, we have successfully fit the absorption spectra and the resonance Raman excitation profile of three fundamental bands at both low temperature and room temperature. With our approach the damping factor is found to be on the order of 50 cm−1 for β-carotene.