Photoion mass spectrometry of adenine, thymine and uracil in the 6–22eV photon energy range

Jochims, H.‐W.; Schwell, Martin; Baumgärtel, H.; Leach, Sydney

doi:10.1016/j.chemphys.2005.03.008

Cited by 185 publications

(431 citation statements)

References 87 publications

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“…This is consistent with a recently proposed interpretation [11] linking the fragment ion to a theoreticallypredicted ring-opening process at the S 2 (ππ*)-S 1 (σ(n-π)π*) crossing seam [9]. [7,5,6]), 70 (C3H4NO + [30,33]), and 85 (C3H5N2O + or C3H3NO2 + ). B The uncertainty estimations on the Gaussian center values are based on summing the uncertainties given by the fitting software (Origin 8.5.1) and the uncertainty based on the calibration.…”

Section: Discussionsupporting

confidence: 77%

“…3b). This supports the assignment of these peaks to are also consistent with the previous assignments to C 3 H 2 NO + and C 3 H 3 NO + from uracil [30,32,33]. It is interesting to note that Fig.…”

supporting

confidence: 79%

“…CH + ions were produced from uracil, both in the present data (albeit weakly) and in previous MPI and EII experiments [11,31]. The fact that CH + ions were not produced from the Imhoff et al [31] and N + by Jochims et al [30]. The present high-resolution measurement shows that CH 2 + dominates.…”

Section: Low-mass Fragment Ion Production From Uracil + and Deuteratesupporting

confidence: 56%

“…5c can be partially explained by relatively efficient access to slow deactivation routes from S 2 (notably internal conversion to S 0 via S 1 ) in adenine. Adenine's lower ionization energy [30] is expected to further increase its MPI efficiency in the present laser beam conditions, while access to triplet states [46,10,8] can also play a role. Additionally, the A + signal may be enhanced by MPI via long-lived exciplex states in π-stacked nucleobases [1,47].…”

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

confidence: 99%

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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: Discussionsupporting

confidence: 77%

supporting

confidence: 79%

Section: Low-mass Fragment Ion Production From Uracil + and Deuteratesupporting

confidence: 56%

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

confidence: 99%

See 2 more Smart Citations

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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“…[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 . Fragmentation in D 5 and D 6 is energetically allowed and expected since these states lie over 4 eV above D 0 and this energy can be used for dissociation over the barriers.…”

Section: Resultsmentioning

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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Einfluss der Solvatisierung auf die Elektronenanlagerung an Pyrimidin

et al. 2015

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Die Wechselwirkung niederenergetischer Elektronen mit Biomolekülen spielt eine wichtige Rolle bei der strahlungsinduzierten Mutation von biologischem Gewebe auf molekularer Ebene.Bei Elektronenenergien unter 15 eV ist die dissoziative Elektronenanlagerung einer der Hauptprozesse, die chemische Umwandlungen von Molekülen induzieren. Bisherige Gasphasenstudien hinsichtlich der ablaufenden Prozesse auf molekularer Ebene wurden mit einzelnen Biomolekülbausteinen wie Pyrimidin als Modellmolekül durchgeführt. Hier wurde die Elektronenanlagerung sowohla n einzelnen Pyrimidinmolekülen als auchr einen oder hydratisierten Clustern untersucht. Im Unterschied zum isolierten und hydratisierten Fall, in denen kein anionisches Monomer detektiert werden konnte,gelang es,das Molekülanion bei reinen Clustern zu beobachten. Zusätzlich gibt es Hinweise darauf, dass die Fragmentierung des Pyrimidinrings unter Elektroneneinfang durch Solvatisierung effizient unterdrücktwird.

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Photoion mass spectrometry of adenine, thymine and uracil in the 6–22eV photon energy range

Cited by 185 publications

References 87 publications

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

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

Strong-Field Molecular Ionization from Multiple Orbitals

Einfluss der Solvatisierung auf die Elektronenanlagerung an Pyrimidin

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