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Record W1977651899 · doi:10.1021/jp034804n

Dehydrogenation and Other Non-radiative Relaxation Processes in Gas-Phase Metal−DNA Base Complexes

2003· article· en· W1977651899 on OpenAlexaff
David Bue Pedersen, Marek Z. Zgierski, Benoît Simard

Bibliographic record

VenueThe Journal of Physical Chemistry A · 2003
Typearticle
Languageen
FieldPhysics and Astronomy
TopicAdvanced Chemical Physics Studies
Canadian institutionsSteacie Institute for Molecular Sciences
Fundersnot available
KeywordsDehydrogenationChemistryGuaninePhotoionizationPhotochemistryRelaxation (psychology)Excited stateMetalDensity functional theoryAdductNucleobaseAtomic physicsComputational chemistryDNAOrganic chemistryCatalysisIonizationPhysicsIon

Abstract

fetched live from OpenAlex

Photoinduced dehydrogenations of gas-phase Al−guanine, Mn−guanine, and the Al-base pair adduct Al−guanine−cytosine have been observed. Upper and lower limits on the minimum photon energy required to effect the dehydrogenation have been determined for these species. Species were generated using a laser ablation source and were detected with laser photoionization/time-of-flight mass spectrometry. Only metalated species were observed to dehydrogenate, and the effect of metal on the photochemistry of guanine and cytosine has been investigated using density functional theory (DFT). Avoided crossings between the ground and first electronically excited states are features specific to the metalated species and are likely responsible for the metal-specific dehydrogenation observed. The rapid nonradiative relaxation believed to manifest the dehydrogenation is consistent with the dominance of multiphoton contributions to the mass spectral signals observed which also stems from rapid nonradiative relaxation. In this context, the photophysics of the gas-phase complexes is similar to that of solution-phase bases where nonradiative relaxation processes also dominate.

Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.

How this classification was reachedexpand

Full frame machine prediction

Teacher imitation

Not calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.

metaresearch head score (Codex)0.000
metaresearch head score (Gemma)0.001
Version: metacan-v3-hybrid-931329e0061cValidation status: machine_predicted_unvalidated
Candidate categoriesnone
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Bench or experimental · Consensus signal: Bench or experimental
GenreCandidate signal: Empirical · Consensus signal: Empirical
Teacher disagreement score0.002
Threshold uncertainty score0.006

Distilled classifier scores by category (both heads)

CategoryCodexGemma
Metaresearch0.0000.001
Meta-epidemiology (narrow)0.0000.000
Meta-epidemiology (broad)0.0000.000
Bibliometrics0.0000.000
Science and technology studies0.0000.000
Scholarly communication0.0000.000
Open science0.0000.000
Research integrity0.0000.000
Insufficient payload (model declined to judge)0.0020.000

Machine scores (provisional)

The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.

Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.

Opus teacher head0.013
GPT teacher head0.278
Teacher spread0.265 · how far apart the two teachers sit on this one work
Validation statusscore_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it

Classification

machine, unvalidated

Machine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.

The models applied no category: nothing in the taxonomy fit this work.
Study designBench or experimental
Domainnot available
GenreEmpirical

How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".

Quick stats

Citations5
Published2003
Admission routes1
Has abstractyes

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