Optical dephasing and electron-phonon interaction in β-carotene solutions

Abstract

Fluorescence spectra of β-carotene in ethanol measured in a temperature range from liquid to solid phases of solvent are compared with a model calculation, assuming a linear electron-phonon interaction with a phonon density of states weighted by coupling constant, ϱ(ω) ∝ ωe − ω ω p . We obtain a peak phonon energy ω p = 28 cm −1, a lattice relaxation energy E LR = 210 cm −1 and temperature dependences of amplitude of the energy modulation and inhomogeneous width. The ratio E LR ω P ∼- 8 shows that the electron -phonon interaction is near the strong coupling regime in this system.