Dynamic band-shift signal in two-dimensional electronic spectroscopy: A case of bacterial reaction center
| Autor: | David Paleček, Eglė Bukartė, Donatas Zigmantas, Sebastian Westenhoff, Petra Edlund |
|---|---|
| Rok vydání: | 2021 |
| Předmět: |
Physics
010304 chemical physics Spectrum Analysis Photosynthetic Reaction Center Complex Proteins General Physics and Astronomy Electrons Rhodobacter sphaeroides 010402 general chemistry 01 natural sciences Signal Electron spectroscopy 0104 chemical sciences Computational physics symbols.namesake 0103 physical sciences Ultrafast laser spectroscopy symbols Energy level Feynman diagram Physical and Theoretical Chemistry Spectroscopy Excitation Energy (signal processing) |
| Zdroj: | The Journal of Chemical Physics. 154:115102 |
| ISSN: | 1089-7690 0021-9606 |
| Popis: | Optical nonlinear spectroscopies carry a high amount of information about the systems under investigation; however, as they report polarization signals, the resulting spectra are often congested and difficult to interpret. To recover the landscape of energy states and physical processes such as energy and electron transfer, a clear interpretation of the nonlinear signals is prerequisite. Here, we focus on the interpretation of the electrochromic band-shift signal, which is generated when an internal electric field is established in the system following optical excitation. Whereas the derivative shape of the band-shift signal is well understood in transient absorption spectroscopy, its emergence in two-dimensional electronic spectroscopy (2DES) has not been discussed. In this work, we employed 2DES to follow the dynamic band-shift signal in reaction centers of purple bacteria Rhodobacter sphaeroides at 77 K. The prominent two-dimensional derivative-shape signal appears with the characteristic formation time of the charge separated state. To explain and characterize the band-shift signal, we use expanded double-sided Feynman diagram formalism. We propose to distinguish two types of Feynman diagrams that lead to signals with negative amplitude: excited state absorption and re-excitation. The presented signal decomposition and modeling analysis allows us to recover precise electrochromic shifts of accessory bacteriochlorophylls, identify additional signals in the B band range, and gain a further insight into the electron transfer mechanism. In a broader perspective, expanded Feynman diagram formalism will allow for interpretation of all 2D signals in a clearer and more intuitive way and therefore facilitate studying the underlying photophysics. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|