All-trans-β-carotene absorption shift and electron-phonon coupling modulated by solvent polarizability

Absorption, resonance Raman spectra are reported on all-trans-beta-carotene dissolved in different polarizability solvents. The absorption spectra of all-trans-beta-carotene are analyzed by Franck-Condon principle and the Huang-Rhys factors are calculated. With the increasing solvent polarizability, the Huang-Rhys factor and the electron-phonon coupling constant decrease, while the Raman scattering cross section increases. The red-shift of absorption would leads to an increasing spectral overlap with the laser excitation leading to an enhanced resonance effect. Through electron-phonon coupling, the ground state structure of all-trans-beta-carotene will be modulated by the electronic transition and is assumed to lead to a modulation of energy flow. Results present insights on the solvent's polarizability dependence on electron-phonon coupling of carotenoid. This work is expected to be helpful for exploring the surrounding medium effects on the electronic transition and carbon carbon vibrations. (C) 2017 Published by Elsevier B.V.