Sub-10 fs time resolved study of excited state relaxation in all-trans-β-carotene

Abstract

The ultrafast internal conversion S 2→S 1 following photoexcitation in all-trans-β-carotene is studied with unprecedented time resolution. Sub-10 fs optical pulses are used to excite and probe the optical dynamics of the molecule dissolved in solution. We observed the ultrafast decay of the stimulated emission from S 2 and formation of the absorption band assigned to S 1→S n transitions within 500 fs. Periodic oscillations of the amplitude are superimposed to the transient transmission difference and assigned to ground state nuclear wavepacket motion excited via impulsive Raman scattering.