Wavelength-dependent photoproduct formation of phycocyanobilin in solution – Indications for competing reaction pathways

Dietzek, Benjamin; Fey, Sonja; Matute, Ricardo A.; González, Leticia; Schmitt, Michael; Popp, Juergen; Yartsev, Arkady; Hermann, Gudrun

doi:10.1016/j.cplett.2011.08.086

Cited by 3 publications

(12 citation statements)

References 35 publications

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“…The time constant τ 3 = 67 ps, revealed by our experiments, is significantly shorter than that given earlier (170-350 ps), possibly due to our explicit consideration of a long living photoproduct in comparison to Ref. [31] and [29,32]. Our data are thus consistent with the reaction scheme proposed earlier (ibid.)…”

Section: Long Timescalessupporting

confidence: 90%

“…In conclusion, the results of our UV/Vis fs-TA-measurements are comparable to those presented in Ref. [31] and [29,32], in particular concerning transient difference spectra and their kinetic analysis. The time constant τ 3 = 67 ps, revealed by our experiments, is significantly shorter than that given earlier (170-350 ps), possibly due to our explicit consideration of a long living photoproduct in comparison to Ref.…”

Section: Long Timescalessupporting

confidence: 88%

“…We suggest the instantaneously emerging CA1 and CA2 to result from an ultrafast proton release reaction of PCB B *, occurring within the system response of 0.38 ± 0.02 ps. In the ground state species PCB B , all pyrroleninic nitrogen atoms are assumed to be protonated [15,18,28,32]. Therefore, no intramolecular H-bond network between the pyrroleninic nitrogen atoms is expected.…”

Section: Time Range Of τmentioning

confidence: 99%

“…Fundamental and systematic experimental studies in this direction have been undertaken using excitation wavelength dependent fs-TA spectroscopy in the visible and NIR spectral region in various solvents, as well as time resolved fluorescence measurements and transient population grating spectroscopy [29][30][31][32]. On this solid basis, a set of photoinduced reactions of the three ground state species of PCB in MeOH has been suggested as follows.…”

Section: Introductionmentioning

confidence: 99%

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Ultrafast proton release reaction and primary photochemistry of phycocyanobilin in solution observed with fs-time-resolved mid-IR and UV/Vis spectroscopy

Theiß

Grupe

Lamparter

et al. 2021

Photochem Photobiol Sci

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Deactivation processes of photoexcited (λex = 580 nm) phycocyanobilin (PCB) in methanol were investigated by means of UV/Vis and mid-IR femtosecond (fs) transient absorption (TA) as well as static fluorescence spectroscopy, supported by density-functional-theory calculations of three relevant ground state conformers, PCBA, PCBB and PCBC, their relative electronic state energies and normal mode vibrational analysis. UV/Vis fs-TA reveals time constants of 2.0, 18 and 67 ps, describing decay of PCBB*, of PCBA* and thermal re-equilibration of PCBA, PCBB and PCBC, respectively, in line with the model by Dietzek et al. (Chem Phys Lett 515:163, 2011) and predecessors. Significant substantiation and extension of this model is achieved first via mid-IR fs-TA, i.e. identification of molecular structures and their dynamics, with time constants of 2.6, 21 and 40 ps, respectively. Second, transient IR continuum absorption (CA) is observed in the region above 1755 cm−1 (CA1) and between 1550 and 1450 cm−1 (CA2), indicative for the IR absorption of highly polarizable protons in hydrogen bonding networks (X–H…Y). This allows to characterize chromophore protonation/deprotonation processes, associated with the electronic and structural dynamics, on a molecular level. The PCB photocycle is suggested to be closed via a long living (> 1 ns), PCBC-like (i.e. deprotonated), fluorescent species.

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Section: Long Timescalessupporting

confidence: 90%

Section: Long Timescalessupporting

confidence: 88%

Section: Time Range Of τmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Ultrafast proton release reaction and primary photochemistry of phycocyanobilin in solution observed with fs-time-resolved mid-IR and UV/Vis spectroscopy

Theiß

Grupe

Lamparter

et al. 2021

Photochem Photobiol Sci

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“…Vertical simulations does not allow for adequate treatment of wavelength dependent photochemical processes, as we encounter e.g. photochemistry of heterocycles 16 , photolysis of glyoxal 17 , photoinitiating reactions 18 or chemistry of phytochromophores 19 (1)…”

Section: Introductionmentioning

confidence: 99%

On the importance of initial conditions for excited-state dynamics

et al. 2018

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Photodynamical simulations are increasingly used to explore photochemical mechanisms and interpret laser experiments. The vast majority of ab initio excited-state simulations are performed within semiclassical, trajectory-based approaches. Apart from underlying electronic-structure theory, the reliability of simulations is controlled by a selection of initial conditions for the classical trajectories. We discuss appropriate choices of initial conditions for simulations of different experimental arrangements: dynamics initiated by continuum-wave (CW) laser fields or triggered by ultrashort laser pulses. We introduce a new technique, CW-sampling, to treat the former case, based on the ideas of importance sampling, combined with the quantum thermostat approach based on the Generalized Langevin Equation (GLE) that allows for efficient sampling of both position and momentum space. The CW-sampling is particularly important for photodynamical processes initiated by absorption at the tail of the UV absorption spectrum. We also emphasize the importance of non-Condon effects for the dynamics. We demonstrate the performance of our approach on the photodissociation of the CF2Cl2 molecule (Freon CFC-12). A quantitative agreement with the experimental data is achieved with the use of empirical correlation energy correction (CEC) factor on top of FOMO-CASCI potential energy surfaces.

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On the Wavelength-Dependent Photochemistry of the Atmospheric Molecule CF₃COCl

Janoš,

Vinklárek,

Rakovský

et al. 2023

ACS Earth Space Chem.

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The wavelength control of photochemistry usually results from ultrafast dynamics following the excitation of different electronic states. Here, we investigate the CF3COCl molecule, exhibiting wavelength-dependent photochemistry both via (i) depositing increasing internal energy into a single state and (ii) populating different electronic states. We reveal the mechanism behind the photon-energy dependence by combining nonadiabatic ab initio molecular dynamics techniques with the velocity map imaging experiment. We describe a consecutive mechanism of photodissociation where an immediate release of Cl taking place in an excited electronic state is followed by a slower ground-state dissociation of the CO fragment. The CO release is subject to an activation barrier and is controlled by excess internal energy via the excitation wavelength. Therefore, a selective release of CO along with Cl can be achieved. The mechanism is fully supported by both the measured kinetic energy distributions and anisotropies of the angular distributions. Interestingly, the kinetic energy of the released Cl atom is sensitively modified by accounting for spin–orbit coupling. Given the atmospheric importance of CF3COCl, we discuss the consequences of our findings for atmospheric photochemistry.

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Wavelength-dependent photoproduct formation of phycocyanobilin in solution – Indications for competing reaction pathways

Cited by 3 publications

References 35 publications

Ultrafast proton release reaction and primary photochemistry of phycocyanobilin in solution observed with fs-time-resolved mid-IR and UV/Vis spectroscopy

Ultrafast proton release reaction and primary photochemistry of phycocyanobilin in solution observed with fs-time-resolved mid-IR and UV/Vis spectroscopy

On the importance of initial conditions for excited-state dynamics

On the Wavelength-Dependent Photochemistry of the Atmospheric Molecule CF₃COCl

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Wavelength-dependent photoproduct formation of phycocyanobilin in solution – Indications for competing reaction pathways

Cited by 3 publications

References 35 publications

Ultrafast proton release reaction and primary photochemistry of phycocyanobilin in solution observed with fs-time-resolved mid-IR and UV/Vis spectroscopy

Ultrafast proton release reaction and primary photochemistry of phycocyanobilin in solution observed with fs-time-resolved mid-IR and UV/Vis spectroscopy

On the importance of initial conditions for excited-state dynamics

On the Wavelength-Dependent Photochemistry of the Atmospheric Molecule CF3COCl

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Product

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On the Wavelength-Dependent Photochemistry of the Atmospheric Molecule CF₃COCl