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Record W2004751027 · doi:10.1063/1.1490593

Amorphous solid water’s isotopic exchange kinetics

2002· article· en· W2004751027 on OpenAlexafffund
G. P. Johari

Bibliographic record

VenueThe Journal of Chemical Physics · 2002
Typearticle
Languageen
FieldMaterials Science
TopicMaterial Dynamics and Properties
Canadian institutionsMcMaster University
FundersNatural Sciences and Engineering Research Council of Canada
KeywordsKineticsChemistryMoleculeProtonCluster (spacecraft)Amorphous solidExponentKinetic isotope effectDiffusionReaction rate constantChemical physicsCrystallographyThermodynamicsComputational chemistryPhysical chemistryDeuteriumAtomic physicsPhysicsOrganic chemistry

Abstract

fetched live from OpenAlex

The mechanism for isotopic exchange by proton hopping and subsequent reorientation of H2O molecules in vapor-deposited, 0.1 mol % 2-naphthol containing amorphous solid water [M. Fischer and J. P. Devlin, J. Phys. Chem. 99, 11584 (1995)] has been reconsidered and an alternative mechanism in terms of diffusion controlled reactions is proposed. In this mechanism, H2O molecules diffuse within the H-bonded clusters, with or without a net increase in the number of H bonds, and isotopic exchange occurs by two processes: (i) Random diffusion of molecules in two clusters, one containing D2O and the other H3O+, leads to formation of an intercluster H bond, which in turn provides a path for proton hopping and converts one D2O (plus one H2O) to two coupled HODs by proton translocation and subsequent orientation. (ii) One H bond between two HOD neighbors in a cluster breaks and reforms with another H2O in the same cluster or in a different cluster, and hence a coupled HOD is converted to an uncoupled HOD. The decrease in D2O and the increase in HOD concentrations with time follow a stretched exponential kinetics, with exponent of 0.65 for the former and 0.54 for the latter process at 122 K. This is equivalent to the time-dependent rate constant in Plonka’s formalism [J. Chem. Phys. 96, 1128 (1992)] and is seen as characteristic of dispersive kinetics. Because fluctuation of the environment is slower than the time scale of overall barrier crossing, the mass-controlled kinetics equations do not apply to a consecutive reaction scheme. The known variation of the isotopic species concentration with time seems to be consistent with this reaction kinetics.

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 distilled prediction

Teacher imitation

Not calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.

metaresearch head score (Codex)0.000
metaresearch head score (Gemma)0.000
Version: codex-gemma-dda1882f352aValidation status: machine_predicted_unvalidated
Candidate categoriesInsufficient payload (model declined to judge)
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 score0.006
Threshold uncertainty score1.000

Codex and Gemma teacher scores by category

CategoryCodexGemma
Metaresearch0.0000.000
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)0.0010.000

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 head0.024
GPT teacher head0.221
Teacher spread0.197 · 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 teacher head, not a consensus.

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

Citations10
Published2002
Admission routes2
Has abstractyes

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