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Record W4396692992 · doi:10.1021/acs.jpca.4c00999

The Role of Momentum Partitioning in Covariance Ion Imaging Analysis

2024· article· en· W4396692992 on OpenAlexaff
Tiffany Walmsley, Joseph McManus, Yoshiaki Kumagai, Kiyonobu Nagaya, James Harries, Hiroshi Iwayama, Michael N. R. Ashfold, Mathew Britton, P. H. Bucksbaum, Taran Driver, David Heathcote, Paul Hockett, Andrew Howard, Jason W. L. Lee, Yusong Liu, Edwin Kukk, Dennis Milešević, Russell S. Minns, Akinobu Niozu, Johannes Niskanen, Andrew J. Orr‐Ewing, Shigeki Owada, Patrick A. Robertson, Daniel Rolles, Artem Rudenko, Kiyoshi Ueda, James Unwin, Claire Vallance, M. Brouard, Michael Burt, Felix Allum, Ruaridh Forbes

Bibliographic record

VenueThe Journal of Physical Chemistry A · 2024
Typearticle
Languageen
FieldEngineering
TopicIon-surface interactions and analysis
Canadian institutionsNational Research Council Canada
FundersSLAC National Accelerator LaboratoryH2020 European Research CouncilBasic Energy SciencesJesus College, University of OxfordJesus College, University of CambridgeOffice of ScienceJapan Society for the Promotion of ScienceAcademy of FinlandHelmholtz-GemeinschaftU.S. Department of EnergyLeverhulme TrustUniversity of SouthamptonEngineering and Physical Sciences Research CouncilUK Research and InnovationNational Science Foundation
KeywordsFragmentation (computing)Dissociation (chemistry)IonIonizationExtreme ultravioletFemtosecondCovarianceBreakupPhysicsChemical physicsChemistryAtomic physicsLaserOpticsQuantum mechanicsPhysical chemistryEcologyStatisticsBiologyMathematics

Abstract

fetched live from OpenAlex

We present results from a covariance ion imaging study, which employs extensive filtering, on the relationship between fragment momenta to gain deeper insight into photofragmentation dynamics. A new data analysis approach is introduced that considers the momentum partitioning between the fragments of the breakup of a molecular polycation to disentangle concurrent fragmentation channels, which yield the same ion species. We exploit this approach to examine the momentum exchange relationship between the products, which provides direct insight into the dynamics of molecular fragmentation. We apply these techniques to extensively characterize the dissociation of 1-iodopropane and 2-iodopropane dications prepared by site-selective ionization of the iodine atom using extreme ultraviolet intense femtosecond laser pulses with a photon energy of 95 eV. Our assignments are supported by classical simulations, using parameters largely obtained directly from the experimental data.

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)0.001
metaresearch head score (Gemma)0.006
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 score0.008

Distilled classifier scores by category (both heads)

CategoryCodexGemma
Metaresearch0.0010.006
Meta-epidemiology (narrow)0.0000.000
Meta-epidemiology (broad)0.0000.000
Bibliometrics0.0010.001
Science and technology studies0.0010.001
Scholarly communication0.0010.002
Open science0.0010.001
Research integrity0.0000.001
Insufficient payload (model declined to judge)0.0010.000

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 head0.002
GPT teacher head0.215
Teacher spread0.213 · 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

Citations6
Published2024
Admission routes1
Has abstractyes

Explore more

Same venueThe Journal of Physical Chemistry ASame topicIon-surface interactions and analysisFrench-language works237,207