title: Direct observation of the coherent nuclear response after the absorption of a photon.
abstract: How molecules convert light energy to perform a specific transformation is a fundamental question in photophysics. Ultrafast spectroscopy reveals the kinetics associated with electronic energy flow, but little is known about how absorbed photon energy drives nuclear motion. Here we used ultrabroadband transient absorption spectroscopy to monitor coherent vibrational energy flow after photoexcitation of the retinal chromophore. In the proton pump bacteriorhodopsin, we observed coherent activation of hydrogen-out-of-plane wagging and backbone torsional modes that were replaced by unreactive coordinates in the solution environment, concomitant with a deactivation of the reactive relaxation pathway.
authors: Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom.
authors: M
authors: M
authors: Liebel
authors: Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom.
authors: C
authors: C
authors: Schnedermann
authors: Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom.
authors: G
authors: G
authors: Bassolino
authors: Department of Biochemistry, Biomembrane Structure Unit, University of Oxford, Oxford OX1 3QU, United Kingdom.
authors: G
authors: G
authors: Taylor
authors: Department of Biochemistry, Biomembrane Structure Unit, University of Oxford, Oxford OX1 3QU, United Kingdom.
authors: A
authors: A
authors: Watts
authors: Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom.
authors: P
authors: P
authors: Kukura
mesh_terms: D000042:Absorption; D001436:Bacteriorhodopsins / Q000737:chemistry*; D007700:Kinetics; D055668:Photochemical Processes; D017785:Photons; D012172:Retinaldehyde / Q000737:chemistry*; D012545:Schiff Bases / Q000737:chemistry*; D019265:Spectroscopy, Near-Infrared / Q000379:methods; D013059:Spectrum Analysis, Raman / Q000379:methods; D013816:Thermodynamics; D014732:Vibration
chemical_list: D012545:Schiff Bases; D001436:Bacteriorhodopsins; D012172:Retinaldehyde