Using fluorescence detected two-dimensional spectroscopy to investigate initial exciton delocalization between coupled chromophores

Schröter, Marco; Pullerits, Tõnu; Kühn, Oliver

doi:10.1063/1.5046645

Cited by 30 publications

(38 citation statements)

References 48 publications

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“…This is particularly true for multichromophoric systems, for which theory has only been developed for monomer and dimer systems. 4,11−13 The aim of this paper is to develop a relatively simple theory framework to model the spectra of multichromophoric systems such as the Q y band of light-harvesting system 2 (LH2). Using this framework, we aim to understand the origin of the unexpected large cross-peaks reported in such experiments 7,12,14 as well as the observed differences in line shapes.…”

Section: Introductionmentioning

confidence: 99%

“…Along these lines, recent theoretical works, based on a simplified dimer model, support the assertion that the presence of cross-peaks in the F-2DES experiment corresponds to GSB signals indicating a common ground state. 11,13 Here, we will examine the origin of these effects by developing the theory for protein structure-based multichromophore simulations of F-2DES and 2DES spectra of the LH2 complex.…”

Section: Introductionmentioning

confidence: 99%

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Simulating Fluorescence-Detected Two-Dimensional Electronic Spectroscopy of Multichromophoric Systems

et al. 2018

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We present a theory for modeling fluorescence-detected two-dimensional electronic spectroscopy of multichromophoric systems. The theory is tested by comparison of the predicted spectra of the light-harvesting complex LH2 with experimental data. A qualitative explanation of the strong cross-peaks as compared to conventional two-dimensional electronic spectra is given. The strong cross-peaks are attributed to the clean ground-state signal that is revealed when the annihilation of exciton pairs created on the same LH2 complex cancels oppositely signed signals from the doubly excited state. This annihilation process occurs much faster than the nonradiative relaxation. Furthermore, the line shape difference is attributed to slow dynamics, exciton delocalization within the bands, and intraband exciton–exciton annihilation. This is in line with existing theories presented for model systems. We further propose the use of time-resolved fluorescence-detected two-dimensional spectroscopy to study state-resolved exciton–exciton annihilation.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Simulating Fluorescence-Detected Two-Dimensional Electronic Spectroscopy of Multichromophoric Systems

et al. 2018

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Section: Figurementioning

confidence: 99%

“…However, it has been pointed out that the cross peak behaviour is not trivial. 19,20 For example, the cross peak amplitude can increase while the coupling strength is decreasing. Still, if structure is known, the exciton mixing angle can be evaluated.Alternatively, instead of focusing on the cross peak amplitude/strength, one could construct a signal analogous to the so-called two colour photon echo peak-shift experiment.…”

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confidence: 99%

Interpreting Fluorescence Detected Two-Dimensional Electronic Spectroscopy

Kühn

Mančal

Pullerits

2020

J. Phys. Chem. Lett.

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Electronic coherent multidimensional spectroscopy (CMDS) allows detailed studies of ultrafast dynamics in systems with highly congested complicated spectral bands. 1,2,3 A wide variety of experimental implementations have been developed 4 emphasising different strengths of the methodology. Originally, the 2D electronic spectroscopy (2DES) was based on phase-sensitive detection of a coherent photon-echo type signal generated by three laser pulses. 5,6 During the last decade four-pulse generated incoherent action detection has become popular. The concept was originally developed for fluorescence detected 2DES (F-2DES). 7 Later numerous other incoherent action detection methods have been used, e.g., based on photoelectrons, 8 photocurrents 9,10 and photo ions. 11 Even though 2DES and F-2DES are analogous coherent techniques providing detailed information on ultrafast dynamics in two spectral dimensions, the methods have important differences and the measured spectra do not look the same. 12,13,14,15 While the "anatomy" of the 2DES has been studied in numerous articles 16,17,18 and is quite well understood, interpretation of the F-2DES spectra 19,20,21,22,23 has not reached similar maturity and is currently being debated in literature. In this Viewpoint we briefly summarize the various approaches to interpreting the F-2DES and present our view with the intension to resolve at least some of the existing controversial issues. We start from a brief summary of the two methods.In 2DES the third order macroscopic polarization induced by three short laser pulses generates various coherent light fields in different phase-matched directions. For phase-sensitive detection the coherent field of a certain phase-matched direction is mixed with a fourth, so called local oscillator pulse and spectrally dispersed in a spectrometer. The Fourier transform of the delay between the first two pulses provides the excitation frequency axis (usually horizontal) and the spectrum of the coherent photon echo and free induction decay type signal fields give the detection axis (usually vertical).In F-2DES four laser pulses bring the system to a fourth-order excited state population which is detected via the emitted fluorescence. For disentangling the detected signal into the components of interest, phase modulation of the pulses together with lock-in detection is used. 24,25 Alternatively, in phase cycling, a certain set of phase combinations of the pulses is applied thereby allowing to uniquely determine the signals of interest. 26 Conceptually, there are three important differences between 2DES and F-2DES: 1) Since F-2DES has one more excitation pulse, there is an additional signal generating Liouville pathway as can be seen in Figure 1. 2) After the fourth pulse, fluorescence is usually emitted over long time period during which various processes can occur that influence the fluorescence yield and can mix two-pulse modulations. 27 3) Since in F-2DES disentangling of the signals is achieved by phase modulation and corresponding Fourier filteri...

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“…29 A typical FD2D spectrum of such system with two clear linear absorption bands has four peaks. 30,31,32 In Figure 1 (rightmost), a 2D spectrum of LH2 is shown. The four peaks R11, R12, R21, and R22 can be clearly distinguished.…”

Section: Introductionmentioning

confidence: 99%

Compressed Sensing for Reconstructing Coherent Multidimensional Spectra

et al. 2020

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We apply two sparse reconstruction techniques, the least absolute shrinkage and selection operator (LASSO) and the sparse exponential mode analysis (SEMA), to two-dimensional (2D) spectroscopy. The algorithms are first tested on model data, showing that both are able to reconstruct the spectra using only a fraction of the data required by the traditional Fourier-based estimator. Through the analysis of a sparsely sampled experimental fluorescence detected 2D spectra of LH2 complexes, we conclude that both SEMA and LASSO can be used to significantly reduce the required data, still allowing to reconstruct the multidimensional spectra. Of the two techniques, it is shown that SEMA offers preferable performance, providing more accurate estimation of the spectral line widths and their positions. Furthermore, SEMA allows for off-grid components, enabling the use of a much smaller dictionary than the LASSO, thereby improving both the performance and lowering the computational complexity for reconstructing coherent multidimensional spectra.

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Using fluorescence detected two-dimensional spectroscopy to investigate initial exciton delocalization between coupled chromophores

Cited by 30 publications

References 48 publications

Simulating Fluorescence-Detected Two-Dimensional Electronic Spectroscopy of Multichromophoric Systems

Simulating Fluorescence-Detected Two-Dimensional Electronic Spectroscopy of Multichromophoric Systems

Interpreting Fluorescence Detected Two-Dimensional Electronic Spectroscopy

Compressed Sensing for Reconstructing Coherent Multidimensional Spectra

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