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Record W2060108699 · doi:10.1063/1.1346635

Effects of induced steric hindrance on the dielectric behavior and H bonding in the supercooled liquid and vitreous alcohol

2001· article· en· W2060108699 on OpenAlex

Why this work is in the frame

A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.

affAt least one author lists a Canadian institution in the pinned OpenAlex snapshot.
fundA Canadian funder is recorded on the work.

Bibliographic record

VenueThe Journal of Chemical Physics · 2001
Typearticle
Languageen
FieldMaterials Science
TopicMaterial Dynamics and Properties
Canadian institutionsMcMaster University
FundersNatural Sciences and Engineering Research Council of CanadaEnterprise Ireland
KeywordsSupercoolingSteric effectsArrhenius equationDielectricRelaxation (psychology)Intermolecular forceChemistryThermodynamicsAtmospheric temperature rangeActivation energyPhysical chemistryMoleculeMaterials scienceOrganic chemistry

Abstract

fetched live from OpenAlex

The extent of H bonding in alcohols may be reduced by sterically hindering its OH group. This technique is used here for investigating the reasons for the prominent Debye-type dielectric relaxation observed in monohydroxy alcohols [Kudlik et al., Europhys. Lett. 40, 549 (1997); Hansen et al., J. Chem. Phys. 107, 1086 (1997); Kalinovskaya and Vij, ibid. 112, 3262 (2000)], and broadband dielectric spectroscopy of supercooled liquid and glassy states of 1-phenyl-1-propanol is performed over the 165–238 K range. In its molecule, the steric hindrance from the phenyl group and the existence of optical isomers reduce the extent of intermolecular H bonding. The equilibrium permittivity data show that H-bonded chains do not form in the supercooled liquid, and the total polarization decays by three discrete relaxation processes, of which only the slower two could be resolved. The first is described by the Cole–Davidson-type distribution of relaxation times and a Vogel–Fulcher–Tammann-type temperature dependence of its average rate, which are characteristics of the α-relaxation process as in molecular liquids. The second is described by a Havriliak–Negami-type equation, and an Arrhenius temperature dependence, which are the characteristics of the Johari–Goldstein process of localized molecular motions. The relaxation rate’s non-Arrhenius temperature dependence has been examined qualitatively in terms of the Dyre theory, which considers that the apparent Arrhenius energy itself is temperature dependent, as in the classical interpretations, and quantitatively in terms of the cooperatively rearranging region’s size, without implying that there is an underlying thermodynamic transition in its equilibrium liquid. The relaxation rate also fits the power law with the critical exponent of 13.4, instead of 2–4, required by the mode-coupling theory, thereby indicating the ambiguity of the power-law equations.

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.

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)0.001
metaresearch head score (Gemma)0.000
Version: codex-gemma-dda1882f352aValidation 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 score0.001
Threshold uncertainty score0.156

Codex and Gemma teacher scores by category

CategoryCodexGemma
Metaresearch0.0010.000
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)0.0000.000

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 head0.018
GPT teacher head0.240
Teacher spread0.222 · 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