Cytosine excited state dynamics studied by femtosecond fluorescence upconversion and transient absorption spectroscopy

Sharonov, A.; Gustavsson, T.; Carré, Vincent; Renault, Eric; Markovitsi, Dimitra

doi:10.1016/j.cplett.2003.09.021

Cited by 50 publications

(39 citation statements)

References 25 publications

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“…They wrote in their study that a ~100 ps life time is rather long for monomer-like fluorescence, but suggested that this could be due to restricted solvent exposure [19]. This explanation is contradicted, however, by recent results showing fluorescence lifetimes of ≤1 ps for monomeric bases in a variety of solvents [47][48][49].…”

Section: Hemiprotonated Self-associated Structuresmentioning

confidence: 52%

Ultrafast excited-state dynamics of RNA and DNA C tracts

2008

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The excited-state dynamics of the RNA homopolymer of cytosine and of the 18-mer (dC) 18 were studied by steady-state and time-resolved absorption and emission spectroscopy. At pH 6.8, excitation of poly(rC) by a femtosecond UV pump pulse produces excited states that decay up to one order of magnitude more slowly than the excited states formed in the mononucleotide cytidine 5'-monophosphate under the same conditions. Even slower relaxation is observed for the hemiprotonated, self-associated form of poly(rC), which is stable at acidic pH. Transient absorption and time-resolved fluorescence signals for (dC) 18 at pH 6.8 are similar to ones observed for poly(rC) near pH 4, indicating that hemiprotonated structures are found in DNA C tracts at neutral pH. In both systems, there is evidence for two kinds of emitting states with lifetimes of ~100 ps and slightly more than 1 ns. The former states are responsible for the bulk of emission from the hemiprotonated structures. Evidence suggests that slow electronic relaxation in these self-complexes is the result of vertical base stacking. The similar signals from RNA and DNA C tracts suggest a common basestacked structure, which may be identical with that of i-motif DNA.

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Section: Hemiprotonated Self-associated Structuresmentioning

confidence: 52%

Ultrafast excited-state dynamics of RNA and DNA C tracts

2008

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“…The full multiple spawning ͑FMS͒ method [19][20][21][22][23][24][25] meets these requirements, and has been successfully applied to photoisomerization in various hydrocarbons, 4,19 excited-state proton transfer in salicylic acid derivatives, 26,27 energy transfer in phenylacetylene dendrimers, 28,29 and photochemistry in DNA bases. 30,31 In addition, it is relatively straightforward to recast the results of a FMS simulation into forms directly comparable to time-resolved photoionization 30,32,33 and fluorescence upconversion 26,30,[34][35][36] signals.…”

Section: Introductionmentioning

confidence: 99%

An “optimal” spawning algorithm for adaptive basis set expansion in nonadiabatic dynamics

Yang¹,

Coe²,

Kaduk³

et al. 2009

The Journal of Chemical Physics

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The full multiple spawning (FMS) method has been developed to simulate quantum dynamics in the multistate electronic problem. In FMS, the nuclear wave function is represented in a basis of coupled, frozen Gaussians, and a "spawning" procedure prescribes a means of adaptively increasing the size of this basis in order to capture population transfer between electronic states. Herein we detail a new algorithm for specifying the initial conditions of newly spawned basis functions that minimizes the number of spawned basis functions needed for convergence. "Optimally" spawned basis functions are placed to maximize the coupling between parent and child trajectories at the point of spawning. The method is tested with a two-state, one-mode avoided crossing model and a two-state, two-mode conical intersection model.

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“…[3][4][5] The main outcome of these and subsequent experimental studies was that the excited state decays were indeed found to be much faster than 1 ps, for all the NABs. [6][7][8][9][10][11] To illustrate this, fluorescence decays for the eight nucleosides and nucleotides are shown in Figure 1.…”

Section: Ultrafast and Effective Non-radiative Decay Routes Exist Formentioning

confidence: 99%

DNA/RNA: Building Blocks of Life Under UV Irradiation

Gustavsson

Improta

Markovitsi

2010

J. Phys. Chem. Lett.

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176

201

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International audienceDuring the last 10 years, intense experimental and theoretical work has proven the existence of ultrafast nonradiative decay routes for UV-excited monomeric nucleic acid bases, accounting for their high photostability. This mechanism has been explained by the occurrence of easily accessible conical intersections connecting the first excited ππ* state with the ground state. However, recent studies of substituent and solvent effects indicate that the situation is more complicated than what was initially thought, notably by the presence of dark excited states. Moreover, the actual shape of the excited-state potential energy surface may induce nonexponential dynamics. Further efforts are needed in order to clarify how various environmental factors affect the structural and dynamical aspects of the nucleic acid base excited states

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Cytosine excited state dynamics studied by femtosecond fluorescence upconversion and transient absorption spectroscopy

Cited by 50 publications

References 25 publications

Ultrafast excited-state dynamics of RNA and DNA C tracts

Ultrafast excited-state dynamics of RNA and DNA C tracts

An “optimal” spawning algorithm for adaptive basis set expansion in nonadiabatic dynamics

DNA/RNA: Building Blocks of Life Under UV Irradiation

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