Following Ultrafast Radiationless Relaxation Dynamics With Strong Field Dissociative Ionization: A Comparison Between Adenine, Uracil, and Cytosine

Kotur, Marija; Weinacht, Thomas; Zhou, Congyi; Matsika, Spiridoula

doi:10.1109/jstqe.2011.2107892

Cited by 44 publications

(66 citation statements)

References 49 publications

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“…5c). Kutor et al's [45] time-resolved pump (262 nm) -probe (780 nm) measurements on gas-phase adenine and uracil showed that parent ion production could be fitted by summing a fast decay component (time constant 100 fs for A + , 70 fs for U + ) and a slow decay component (1.14 ps for A + , 2.15 ps for U + ). Importantly, the slow decay amplitude / the fast decay amplitude was 95% for A + , compared with 9% for U + .…”

Section: Fig 5 Compares Mpi and Eii Measurements Carried Out On Uracmentioning

confidence: 99%

Dissociative multi-photon ionization of isolated uracil and uracil-adenine complexes

Ryszka

Pandey

Rizk

et al. 2016

International Journal of Mass Spectrometry

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Recent multi-photon ionization (MPI) experiments on uracil revealed a fragment ion at m/z 84 that was proposed as a potential marker for ring opening in the electronically excited neutral molecule. The present MPI measurements on deuterated uracil identify the fragment as C 3 H 4 N 2 O + (uracil + less CO), a plausible dissociative ionization product from the theoretically predicted open-ring isomer. Equivalent measurements on thymine do not reveal an analogous CO loss channel, suggesting greater stability of the excited DNA base. MPI and electron impact ionization experiments have been carried out on uracil-adenine clusters in order to better understand the radiation response of uracil within RNA.Evidence for C 3 H 4 N 2 O + production from multi-photon-ionized uracil-adenine clusters is tentatively attributed to a significant population of π-stacked configurations in the neutral beam. Graphical AbstractHighlights UV multi-photon ionization measurements on deuterated uracil have identified a CO loss pathway that may indicate ring opening in the electronically excited neutral molecule. The first dissociative ionization experiments on uracil-adenine complexes have revealed that the CO loss channel is also accessible in these clusters.Keywords: Uracil; adenine-uracil clusters; fragmentation; multi-photon ionization; electron impact ionization; mass spectrometry Ryszka et al. Int. J. Mass. Spectrom. 396 (2016) 48 2 IntroductionThe dynamics and stabilities of nucleobases following excitation to their bright S 2 (ππ* of the ring-opening crossing seam [9] and the geometry of the predicted isomer indicates likely CO abstraction. Therefore MPI production of this fragment ion was proposed as a potential experimental marker for ring opening in neutral excited uracil, suggesting possibilities for diverse measurements exploring the process in depth (e.g. using coincidence and / or time-resolved methods). The first aim of the present work was to test if the new fragment ion is indeed due to CO loss by studying MPI of deuterated uracil (dominantly C 4 D 4 N 2 O 2 ). These results have the added value of identifying several previously debated fragments from the radical cation, while further evidence to assign specific peaks is provided by high-resolution MPI mass spectra. The paper also presents equivalent MPI measurements on thymine, for which no analogous ring-opening process has been predicted [9]. A distinctly higher pump energy (5.64 eV, 220 nm) was applied than in the previous MPI studies of thymine (4.34-4.77 eV, 285.7-260 nm) [6, 12, 13, 14, 15, 16, 17], increasing the likelihood of isomeric transitions during radiationless deactivation. Finally, MPI and electron impact ionization (EII) experiments were carried out on uracil-adenine clusters as a step towards better understanding the dissociative ionization pathways of uracil within RNA. Whereas several spectroscopic studies have been carried out on adenine-thymine complexes in supersonic beams [18,19,20], to our knowledge no previous experiments on isolated u...

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Section: Fig 5 Compares Mpi and Eii Measurements Carried Out On Uracmentioning

confidence: 99%

Dissociative multi-photon ionization of isolated uracil and uracil-adenine complexes

Ryszka

Pandey

Rizk

et al. 2016

International Journal of Mass Spectrometry

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“…Our approach is able to capture the spread of the lifetimes by observing multiple fragments for a given molecule. [13][14][15] We consider a series of molecules which have been shown to internally convert from an excited state down to the ground state on ultrafast time scales following excitation in the deep UV. We chose systems with and without barriers between the Franck-Condon region on the excited state and CIs that facilitate relaxation in an effort to span a range of decay times.…”

Section: Introductionmentioning

confidence: 99%

The influence of excited state topology on wavepacket delocalization in the relaxation of photoexcited polyatomic molecules

Krause

Matsika

Kotur

et al. 2012

The Journal of Chemical Physics

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This paper compares the relaxation dynamics of several molecules that display internal conversion on ultrafast time scales. We find that the degree of wavefunction localization during relaxation is strongly correlated with the rate of relaxation. We discuss our experimental findings in terms of two-dimensional model simulations which try to capture the essential features of the potential energy landscapes relevant to the relaxation dynamics. Our model calculations show how relaxation can be local or nonlocal depending on basic features of the potential energy surface traversed by the wavepacket en route back to the ground state.

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“…Furthermore, parallel experiments that we have carried out on other molecules with a velocity-map-imaging apparatus show that ionization to excited states of the cation is predominantly followed by dissociation on the ground state of the cation, where fragments are ejected with the maximum possible kinetic energy [34]. [25,32]. The calculated barriers and measured appearance energies [35] for creating fragments 28, 41, and 42 are above 3 eV [32], indicating that these fragments cannot be created from states below D 5 .…”

Section: Resultsmentioning

confidence: 90%

“…The 6-311+G(d,p) basis set was used. More details about the cationic states can be obtained in the original publication [25].…”

Section: Calculationsmentioning

confidence: 99%

Strong-Field Molecular Ionization from Multiple Orbitals

et al. 2011

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We demonstrate strong-field ionization from multiple orbitals of excited-state uracil molecules. The molecules are excited to the first bright state by an ultrafast laser pulse in the deep ultraviolet and then ionized with a strong-field laser pulse in the near infrared during ultrafast relaxation back down to the ground state. We measure time-and angle-dependent ion yields for multiple fragments created by strongfield ionization, and interpret the temporally and angularly resolved yields via ab initio electronic structure calculations. We find that the angular distribution for the electron removed from the lowest unoccupied molecular orbital follows the symmetry of the molecular orbital, whereas ionization of the molecule by removing electrons from deeper bound orbitals is more complicated.

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Following Ultrafast Radiationless Relaxation Dynamics With Strong Field Dissociative Ionization: A Comparison Between Adenine, Uracil, and Cytosine

Cited by 44 publications

References 49 publications

Dissociative multi-photon ionization of isolated uracil and uracil-adenine complexes

Dissociative multi-photon ionization of isolated uracil and uracil-adenine complexes

The influence of excited state topology on wavepacket delocalization in the relaxation of photoexcited polyatomic molecules

Strong-Field Molecular Ionization from Multiple Orbitals

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