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Modelling time-resolved two-dimensional electronic spectroscopy of the primary photoisomerization event in rhodopsin.

Rivalta I, Nenov A, Weingart O, Cerullo G, Garavelli M, Mukamel S - J Phys Chem B (2014)

Bottom Line: Different combinations of pulse frequencies are proposed in order to follow the evolution of specific ESA signals.These include a two-color 2DVis/NIR setup especially suited for tracking the evolution of the S1 → S2 transitions that can be used to discriminate between different photochemical mechanisms of retinal photoisomerization as a function of the environment.The reported results are consistent with the available time-resolved pump-probe experimental data, and may be used for the design of more elaborate transient 2D electronic spectroscopy techniques.

View Article: PubMed Central - PubMed

Affiliation: Université de Lyon , CNRS, Institut de Chimie de Lyon, École Normale Supérieure de Lyon, 46 Allée d'Italie, F-69364 Lyon Cedex 07, France.

ABSTRACT
Time-resolved two-dimensional (2D) electronic spectra (ES) tracking the evolution of the excited state manifolds of the retinal chromophore have been simulated along the photoisomerization pathway in bovine rhodopsin, using a state-of-the-art hybrid QM/MM approach based on multiconfigurational methods. Simulations of broadband 2D spectra provide a useful picture of the overall detectable 2D signals from the near-infrared (NIR) to the near-ultraviolet (UV). Evolution of the stimulated emission (SE) and excited state absorption (ESA) 2D signals indicates that the S1 → SN (with N ≥ 2) ESAs feature a substantial blue-shift only after bond inversion and partial rotation along the cis → trans isomerization angle, while the SE rapidly red-shifts during the photoinduced skeletal relaxation of the polyene chain. Different combinations of pulse frequencies are proposed in order to follow the evolution of specific ESA signals. These include a two-color 2DVis/NIR setup especially suited for tracking the evolution of the S1 → S2 transitions that can be used to discriminate between different photochemical mechanisms of retinal photoisomerization as a function of the environment. The reported results are consistent with the available time-resolved pump-probe experimental data, and may be used for the design of more elaborate transient 2D electronic spectroscopy techniques.

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Related in: MedlinePlus

Broadband 2DES spectra obtained with infinitely broadlaser pulses,using the xxxx nonchiral polarization scheme. 2D spectra are reportedfor the selected MEP point from the FC to the CI (at ∼90°).The complex part of the signal is plotted on a logarithmic scale.The transitions are labeled according to the Figure 2 assignment, with green and light green boxes highlightingthe D and D′ (S1 → S2) transitions,respectively.
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fig3: Broadband 2DES spectra obtained with infinitely broadlaser pulses,using the xxxx nonchiral polarization scheme. 2D spectra are reportedfor the selected MEP point from the FC to the CI (at ∼90°).The complex part of the signal is plotted on a logarithmic scale.The transitions are labeled according to the Figure 2 assignment, with green and light green boxes highlightingthe D and D′ (S1 → S2) transitions,respectively.

Mentions: In the previous section, we havedescribed the evolution of the excited state manifold along the MEPof the photoisomerization, considering those excited states locatedbelow 34 000 cm–1 from S1. Inorder to visualize the energy positions of these electronic transitions,the possible overlaps between signals and the energy shifting trendsof some important transitions, we report in Figure 3 the broadband 2DES spectra calculated using all three laserpulses centered at the absorption maximum frequency of the chromophore(νmax, calculated to be at 20 875cm–1 at the CASPT2/CASSCF level) with infinitelybroad bandwidth. Infinitely broad pulses reveal all signals that are“ideally” detectable, helping in the selection of experimentalparameters (i.e., central probe frequencies and pulse bandwidths)to be used in tailored experiments for the detection of desired electronictransitions.


Modelling time-resolved two-dimensional electronic spectroscopy of the primary photoisomerization event in rhodopsin.

Rivalta I, Nenov A, Weingart O, Cerullo G, Garavelli M, Mukamel S - J Phys Chem B (2014)

Broadband 2DES spectra obtained with infinitely broadlaser pulses,using the xxxx nonchiral polarization scheme. 2D spectra are reportedfor the selected MEP point from the FC to the CI (at ∼90°).The complex part of the signal is plotted on a logarithmic scale.The transitions are labeled according to the Figure 2 assignment, with green and light green boxes highlightingthe D and D′ (S1 → S2) transitions,respectively.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4216198&req=5

fig3: Broadband 2DES spectra obtained with infinitely broadlaser pulses,using the xxxx nonchiral polarization scheme. 2D spectra are reportedfor the selected MEP point from the FC to the CI (at ∼90°).The complex part of the signal is plotted on a logarithmic scale.The transitions are labeled according to the Figure 2 assignment, with green and light green boxes highlightingthe D and D′ (S1 → S2) transitions,respectively.
Mentions: In the previous section, we havedescribed the evolution of the excited state manifold along the MEPof the photoisomerization, considering those excited states locatedbelow 34 000 cm–1 from S1. Inorder to visualize the energy positions of these electronic transitions,the possible overlaps between signals and the energy shifting trendsof some important transitions, we report in Figure 3 the broadband 2DES spectra calculated using all three laserpulses centered at the absorption maximum frequency of the chromophore(νmax, calculated to be at 20 875cm–1 at the CASPT2/CASSCF level) with infinitelybroad bandwidth. Infinitely broad pulses reveal all signals that are“ideally” detectable, helping in the selection of experimentalparameters (i.e., central probe frequencies and pulse bandwidths)to be used in tailored experiments for the detection of desired electronictransitions.

Bottom Line: Different combinations of pulse frequencies are proposed in order to follow the evolution of specific ESA signals.These include a two-color 2DVis/NIR setup especially suited for tracking the evolution of the S1 → S2 transitions that can be used to discriminate between different photochemical mechanisms of retinal photoisomerization as a function of the environment.The reported results are consistent with the available time-resolved pump-probe experimental data, and may be used for the design of more elaborate transient 2D electronic spectroscopy techniques.

View Article: PubMed Central - PubMed

Affiliation: Université de Lyon , CNRS, Institut de Chimie de Lyon, École Normale Supérieure de Lyon, 46 Allée d'Italie, F-69364 Lyon Cedex 07, France.

ABSTRACT
Time-resolved two-dimensional (2D) electronic spectra (ES) tracking the evolution of the excited state manifolds of the retinal chromophore have been simulated along the photoisomerization pathway in bovine rhodopsin, using a state-of-the-art hybrid QM/MM approach based on multiconfigurational methods. Simulations of broadband 2D spectra provide a useful picture of the overall detectable 2D signals from the near-infrared (NIR) to the near-ultraviolet (UV). Evolution of the stimulated emission (SE) and excited state absorption (ESA) 2D signals indicates that the S1 → SN (with N ≥ 2) ESAs feature a substantial blue-shift only after bond inversion and partial rotation along the cis → trans isomerization angle, while the SE rapidly red-shifts during the photoinduced skeletal relaxation of the polyene chain. Different combinations of pulse frequencies are proposed in order to follow the evolution of specific ESA signals. These include a two-color 2DVis/NIR setup especially suited for tracking the evolution of the S1 → S2 transitions that can be used to discriminate between different photochemical mechanisms of retinal photoisomerization as a function of the environment. The reported results are consistent with the available time-resolved pump-probe experimental data, and may be used for the design of more elaborate transient 2D electronic spectroscopy techniques.

Show MeSH
Related in: MedlinePlus