Reaction Dynamics of a Molecular Switch Unveiled by Coherent Two-Dimensional Electronic Spectroscopy

Kullmann, Martin; Ruetzel, Stefan; Buback, Johannes; Nuernberger, Patrick; Brixner, Tobias

doi:10.1021/ja2032037

Cited by 61 publications

(45 citation statements)

References 43 publications

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“…This is why in this study we employed the two-color 2D ES to disentangle the complex energy transfer cascades in FCP following the excitation of the Fx S 2 state. Application of the two-color 2D ES is very rare due to its extreme experimental difficulty [24,[26][27][28][29]. This work is the first application of the two-color 2D ES to a complicated lightharvesting complex.…”

Section: Introductionmentioning

confidence: 99%

Mapping energy transfer channels in fucoxanthin–chlorophyll protein complex

Gelžinis

Butkus

Songaila

et al. 2015

Biochimica et Biophysica Acta (BBA) - Bioenergetics

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Fucoxanthin-chlorophyll protein (FCP) is the key molecular complex performing the light-harvesting function in diatoms, which, being a major group of algae, are responsible for up to one quarter of the total primary production on Earth. These photosynthetic organisms contain an unusually large amount of the carotenoid fucoxanthin, which absorbs the light in the blue-green spectral region and transfers the captured excitation energy to the FCP-bound chlorophylls. Due to the large number of fucoxanthins, the excitation energy transfer cascades in these complexes are particularly tangled. In this work we present the two-color two-dimensional electronic spectroscopy experiments on FCP. Analysis of the data using the modified decay associated spectra permits a detailed mapping of the excitation frequency dependent energy transfer flow with a femtosecond time resolution.

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Section: Introductionmentioning

confidence: 99%

Mapping energy transfer channels in fucoxanthin–chlorophyll protein complex

Gelžinis

Butkus

Songaila

et al. 2015

Biochimica et Biophysica Acta (BBA) - Bioenergetics

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“…This challenging entanglement of geometry and electronic character makes the MCs an ideal model system for the investigation of the photochemical behavior with ultrafast time-resolved techniques (such as coherent multidimensional spectroscopy 17,18 or transient absorption [9][10][11] ).…”

Section: Introductionmentioning

confidence: 99%

Photoisomerization among ring-open merocyanines. II. A computational study

Walter

Ruetzel

Diekmann

et al. 2014

The Journal of Chemical Physics

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The photochemical isomerization of the trans-trans-cis to the trans-trans-trans isomer of the merocyanine form of 6-nitro BIPS, which has been studied with femtosecond transient absorption spectroscopy [S. Ruetzel, M. Diekmann, P. Nuernberger, C. Walter, B. Engels, and T. Brixner, J. Chem. Phys. 140, 224310 (2014)], is investigated using time-dependent density functional theory in conjunction with polarizable continuum models. Benchmark calculations against SCS-ADC(2) evaluate the applicability of the CAM-B3LYP functional. Apart from a relaxed scan in the ground state with additional computation of the corresponding excitation energies, which produces the excited-state surface vertical to the ground-state isomerization coordinate, a relaxed scan in the S1 gives insight into the geometric changes orthogonal to the reaction coordinate and the fluorescence conditions. The shape of the potential energy surface (PES) along the reaction coordinate is found to be highly sensitive to solvation effects, with the method of solvation (linear response vs. state-specific) being critical. The shape of the PES as well as the computed harmonic frequencies in the S1 minima are in line with the experimental results and offer a straightforward interpretation.

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“…1B) visualizes the photochemical connectivity between products and reactants. We have recently proposed how potential photoproducts and the role of higherlying electronic states can be identified in 2D spectra (25,26). For long population times T, negative diagonal peaks (blue) describe population loss due to the photoreaction, whereas positive cross-peaks (red) emerge at points connecting reactants and products, disclosing correlations.…”

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confidence: 99%

Multidimensional spectroscopy of photoreactivity

Ruetzel¹,

Diekmann²,

Nuernberger³

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

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Coherent multidimensional electronic spectroscopy is commonly used to investigate photophysical phenomena such as light harvesting in photosynthesis in which the system returns back to its ground state after energy transfer. By contrast, we introduce multidimensional spectroscopy to study ultrafast photochemical processes in which the investigated molecule changes permanently. Exemplarily, the emergence in 2D and 3D spectra of a cross-peak between reactant and product reveals the cis-trans photoisomerization of merocyanine isomers. These compounds have applications in organic photovoltaics and optical data storage. Cross-peak oscillations originate from a vibrational wave packet in the electronically excited state of the photoproduct. This concept isolates the isomerization dynamics along different vibrational coordinates assigned by quantum-chemical calculations, and is applicable to determine chemical dynamics in complex photoreactive networks.photoreactive processes | ultrafast spectroscopy | 2D spectroscopy | vibrational coherence A basic objective of physical chemistry is to determine the mechanisms underlying chemical reactions. Fundamental insights into these are provided by femtosecond time-resolved spectroscopy, even below the timescale of molecular vibrations (1). The major challenge of ultrafast photochemistry is to identify isolated signatures of reactants, intermediates, and products, whose spectral bands often overlap. Here we show that such ambiguities are unraveled by coherent multidimensional electronic spectroscopy, e.g., 2D and 3D spectroscopy, where the correlation of a system's excitation and emission frequencies is measured separating features that otherwise superpose. We detect photoreactivity directly via cross-peaks in multidimensional spectra. This opens the broad field of femtochemistry (1) to the multidimensional concept.Two-dimensional electronic spectroscopy (2-5) was primarily implemented for studying photophysical phenomena such as energy transfer in multichromophore light-harvesting systems or other excitonically coupled systems (6-11). Recently, charge transfer has also been investigated (12, 13). Here we are interested in photochemical processes leading to ground-state product species with a molecular configuration that is different from the initial reactant. As a general extension of 2D spectroscopy, 3D representations provide an even more detailed picture. Coherent 3D spectroscopy has been introduced to infrared spectroscopy (14, 15), and recently to electronic spectroscopy for isolating excitonic coherences (16, 17), for liquid-and gas-phase model systems (18)(19)(20), and for analyzing photosynthetic lightharvesting (21,22). Regarding these approaches, one has to differentiate between fifth-order experiments (14, 15, 19) for effects of higher nonlinearity (e.g., three-point frequency-fluctuation correlation functions) (14) and third-order techniques (20)(21)(22)(23)(24), as demonstrated here to unravel photochemical reactions.The principal idea of multidimensional spectrosc...

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Reaction Dynamics of a Molecular Switch Unveiled by Coherent Two-Dimensional Electronic Spectroscopy

Cited by 61 publications

References 43 publications

Mapping energy transfer channels in fucoxanthin–chlorophyll protein complex

Mapping energy transfer channels in fucoxanthin–chlorophyll protein complex

Photoisomerization among ring-open merocyanines. II. A computational study

Multidimensional spectroscopy of photoreactivity

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