title: Lack of evidence for phase-only control of retinal photoisomerization in the strict one-photon limit.
abstract: The concept of shaping electric fields to steer light-induced processes coherently has fascinated scientists for decades. Despite early theoretical considerations that ruled out one-photon coherent control (CC), several experimental studies reported that molecular responses are sensitive to the shape of the excitation field in the weak-field limit. These observations were largely attributed to the presence of rapid-decay channels, but experimental verification is lacking. Here, we test this hypothesis by investigating the degree of achievable control over the photoisomerization of the retinal protonated Schiff-base in bacteriorhodopsin, isorhodopsin and rhodopsin, all of which exhibit similar chromophores but different isomerization yields and excited-state lifetimes. Irrespective of the system studied, we find no evidence for dissipation-dependent behaviour, nor for any CC in the strict one-photon limit. Our results question the extent to which a photochemical process at ambient conditions can be controlled at the amplitude level, and how the underlying molecular potential-energy surfaces and dynamics may influence this controllability.
authors.affiliation: Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, OX1 3QZ Oxford, UK.
authors.forename: M
authors.initials: M
authors.lastname: Liebel
authors.affiliation: Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, OX1 3QZ Oxford, UK.
authors.forename: P
authors.identifier: 0000-0003-0136-7704
authors.initials: P
authors.lastname: Kukura
mesh_terms: D001436:Bacteriorhodopsins / Q000737:chemistry*; D008027:Light; D008962:Models, Theoretical; D055668:Photochemical Processes; D017785:Photons; D012172:Retinaldehyde / Q000737:chemistry*; D012243:Rhodopsin / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D001436:Bacteriorhodopsins; D012243:Rhodopsin; D012172:Retinaldehyde