title: Vibrationally coherent crossing and coupling of electronic states during internal conversion in β-carotene.
abstract: Coupling of nuclear and electronic degrees of freedom mediates energy flow in molecules after optical excitation. The associated coherent dynamics in polyatomic systems, however, remain experimentally unexplored. Here, we combined transient absorption spectroscopy with electronic population control to reveal nuclear wave packet dynamics during the S2 → S1 internal conversion in β-carotene. We show that passage through a conical intersection is vibrationally coherent and thereby provides direct feedback on the role of different vibrational coordinates in the breakdown of the Born-Oppenheimer approximation.
authors.affiliation: Physical and Theoretical Chemistry Laboratory, South Parks Road, Oxford OX1 3QZ, United Kingdom.
authors.forename: M
authors.initials: M
authors.lastname: Liebel
authors.affiliation: Physical and Theoretical Chemistry Laboratory, South Parks Road, Oxford OX1 3QZ, United Kingdom.
authors.forename: C
authors.initials: C
authors.lastname: Schnedermann
authors.affiliation: Physical and Theoretical Chemistry Laboratory, South Parks Road, Oxford OX1 3QZ, United Kingdom.
authors.forename: P
authors.initials: P
authors.lastname: Kukura
mesh_terms: D055668:Photochemical Processes; D013059:Spectrum Analysis, Raman / Q000379:methods; D013816:Thermodynamics; D041623:Tomography, Optical Coherence / Q000379:methods*; D014732:Vibration; D019207:beta Carotene / Q000737:chemistry*
chemical_list: D019207:beta Carotene