Sub-50 fs broadband absorption spectroscopy with tunable excitation: putting the analysis of ultrafast molecular dynamics on solid ground

Megerle, Uwe; Pugliesi, Igor; Schriever, Christian; Sailer, Christian F.; Riedle, Eberhard

doi:10.1007/s00340-009-3610-0

Cited by 254 publications

(282 citation statements)

References 90 publications

Supporting

Mentioning

276

Contrasting

Unclassified

Order By: Relevance

“…41,42 We used femtosecond transient absorption (TA) spectroscopy 43 to measure the kinetics of the various compounds. Directly after excitation of the lowest 1 (np*) transition, pure BP in MeOH shows the spectrum of the S 1 state with prominent absorption maxima at 340 and 580 nm (Fig.…”

Section: Spectroscopic Resultsmentioning

confidence: 99%

Conformational control of benzophenone-sensitized charge transfer in dinucleotides

Merz

Wenninger

Weinberger

et al. 2013

Phys. Chem. Chem. Phys.

View full text Add to dashboard Cite

Charge transfer in DNA cannot be understood without addressing the complex conformational flexibility, which occurs on a wide range of timescales. In order to reduce this complexity four dinucleotide models 1X consisting of benzophenone linked by a phosphodiester to one of the natural nucleosides X = A, G, T, C were studied in water and methanol. The theoretical work focuses on the dynamics and electronic structure of 1G. Predominant conformations in the two solvents were obtained by molecular dynamics simulations. 1G in MeOH adopts mainly an open geometry with a distance of 12-16 Å between the two aromatic parts. In H 2 O the two parts of 1G form primarily a stacked conformation yielding a distance of 5-6 Å. The low-lying excited states were investigated by electronic structure theory in a QM/MM environment for representative snapshots of the trajectories. Photo-induced intramolecular charge transfer in the S 1 state occurs exclusively in the stacked conformation. Ultrafast transient absorption spectroscopy with 1X reveals fast charge transfer from S 1 in both solvents with varying yields. Significant charge transfer from the T 1 state is only found for the nucleobases with the lowest oxidation potential: in H 2 O, charge transfer occurs with 3.2 Â 10 9 s À1 for 1A and 6.0 Â 10 9 s À1 for 1G. The reorganization energy remains nearly unchanged going from MeOH to the more polar H 2 O. The electronic coupling is rather low even for the stacked conformation with H AB = 3 meV and explains the moderate charge transfer rates. The solvent controls the conformational distribution and therefore gates the charge transfer due to differences in distance and stacking.

show abstract

Section: Spectroscopic Resultsmentioning

confidence: 99%

Conformational control of benzophenone-sensitized charge transfer in dinucleotides

Merz

Wenninger

Weinberger

et al. 2013

Phys. Chem. Chem. Phys.

View full text Add to dashboard Cite

show abstract

“…On the timescale of the experiment, we do not observe a change in optical density which means that no population has returned to the ground state and hence, intersystem crossing seems to be the predominant relaxation channel. white light continua and pump sources (see [5]). …”

Section: Absorption Spectrum and Potential Energy Surfacesmentioning

confidence: 99%

Internal Conversion vs. Intersystem Crossing – What Drives the Dynamics of Cyclic α,β-Enones?

Schalk

Lang²,

Schuurman

et al. 2013

EPJ Web of Conferences

Self Cite

View full text Add to dashboard Cite

show abstract

“…2 The coverage of a wide spectral range requires tuning the probe pulse repeatedly and performing the time scan at each setting. This is where UV/vis transient spectroscopy has an intrinsic advantage, as extremely broad continua are now available 3,4 and can be combined with detectors of a thousand or more pixels.…”

Section: Introductionmentioning

confidence: 99%

Electronic transient spectroscopy from the deep UV to the NIR: unambiguous disentanglement of complex processes

et al. 2013

View full text Add to dashboard Cite

Complex multi-stage relaxation and reaction pathways after the optical excitation of molecules makes the disentanglement of the underlying mechanisms challenging. We present four examples that a new transient spectrometer with excitation fully tunable from the deep UV to the IR and 225 to 1700 nm probing allows for an analysis with greatly reduced ambiguity. The temporal resolution of about 50 fs allows us to resolve all relevant processes. For each example there is a new twist in the sequence of relaxation steps that had previously been overlooked. In malachite green it appears that the importance of the phenyl twisting has been overemphasized and rather a charge transfer state should be considered. In TINUVIN-P the predicted twisting as the driving motion for the ultrafast IC is confirmed and leads to a resolution of the earlier puzzle that the sub-5 ps regime shows kinetics deviating from a pure cooling process despite the sub-ps proton transfer cycle. For the bond cleavage of Ph 2 CH-Cl and Ph 2 CH-Br the degree of electron transfer within the radical pair can now be determined quantitatively and leads to a profound understanding of the long term cation yield. For the first time coherent wavepacket motion in the photoproducts is reported. Last but not least the measurement of the GSB recovery in the deep UV allows for the surprising result, that even after S 2 excitation of cyclopentenones the triplet states are reached with near unity probability within a few picoseconds.

show abstract

Sub-50 fs broadband absorption spectroscopy with tunable excitation: putting the analysis of ultrafast molecular dynamics on solid ground

Cited by 254 publications

References 90 publications

Conformational control of benzophenone-sensitized charge transfer in dinucleotides

Conformational control of benzophenone-sensitized charge transfer in dinucleotides

Internal Conversion vs. Intersystem Crossing – What Drives the Dynamics of Cyclic α,β-Enones?

Electronic transient spectroscopy from the deep UV to the NIR: unambiguous disentanglement of complex processes

Contact Info

Product

Resources

About