Zgrablic, GoranHaacke, StefanChergui, Majed2009-03-182009-03-182009-03-18200710.1016/j.chemphys.2007.05.019https://infoscience.epfl.ch/handle/20.500.14299/36198WOS:00025066580001211504Modulations in the time gated ultrafast fluorescence of the protonated Schiff base of retinal in various solvents are reported, which reflect the creation and evolution of vibrational wave packets due to the torsional mode of retinal of frequency .apprx.120 cm-1. The oscillations are damped in .apprx.400 fs. Their frequency is significantly decreased compared to the case of the protein (170 cm-1), and is insensitive to solvent properties such as the dielec. const. and the viscosity. This, along with previous results on mutants of bacteriorhodopsin, leads us to conclude that in the protein, the isomerization dynamics of retinal is governed by steric effects and by the inhomogeneous distribution of the electrostatic field due to amino-acid residues within the protein pocket. We also discuss the origin of the modulations and conclude that they are impulsively excited via the high frequency modes of retinal.Molecular vibration (coherences; vibrational coherences of the protonated Schiff base of all-trans-retinal in soln.); Isomerization (dynamics; vibrational coherences of the protonated Schiff base of all-trans-retinal in soln.); Reaction kinetics (fluorescence; vibrational coherences of the protonated Schiff base of all-trans-retinal in soln.); Steric effects (isomerization dynamics in relation to; vibrational coherences of the protonated Schiff base of all-trans-retinal in soln.); Frequency (modulationsolvent properties in relation to; vibrational coherences of the protonated Schiff base of all-trans-retinal in soln.); Vibrational frequency (oscillations; vibrational coherences of the protonated Schiff base of all-trans-retinal in soln.); Schiff bases Role: PRP (Properties) (protonatedof retinal; vibrational coherences of the protonated Schiff base of all-trans-retinal in soln.); Electrostatic field (specific distributionisomerization dynamics in relation to; vibrational coherences of the protonated Schiff base of all-trans-retinal in soln.); Solvent effect (time-gated ultrafast fluorescence; vibrational coherences of the protonated Schiff base of all-trans-retinal in soln.); Fluorescence (time-gatedultrafast; vibrational coherences of the protonated Schiff base of all-trans-retinal in soln.); Wave packets (vibrational coherences of the protonated Schiff base of all-trans-retinal in soln.); Retinoids Role: PRP (Properties) (vibrational coherences of the protonated Schiff base of all-trans-retinal in soln.)retinal protonated Schiff base ultrafast fluorescence vibrational coherence; oscillation frequency retinal protonated Schiff base; dielec const retinal protonated Schiff base; viscosity retinal protonated Schiff base; steric effect isomerization dynamics retinal protein complex; electrostatic field inhomogeneous distribution retinal protein complextext::journal::journal article::research article