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Record W1973548423 · doi:10.1021/jp064082a

Nitrogen 1s Near-Edge X-ray Absorption Fine Structure Spectroscopy of Amino Acids:  Resolving Zwitterionic Effects

2006· article· en· W1973548423 on OpenAlex
Edwige Otero, Stephen G. Urquhart

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.

Bibliographic record

VenueThe Journal of Physical Chemistry A · 2006
Typearticle
Languageen
FieldEngineering
TopicSurface Chemistry and Catalysis
Canadian institutionsUniversity of Saskatchewan
Fundersnot available
KeywordsXANESValence (chemistry)ChemistryX-ray absorption fine structureAb initioAbsorption spectroscopyRydberg formulaSpectroscopyExtended X-ray absorption fine structureSpectral lineAb initio quantum chemistry methodsMoleculeAmino acidQuenching (fluorescence)CrystallographyIonizationComputational chemistryOrganic chemistryPhysicsFluorescenceIon

Abstract

fetched live from OpenAlex

Considerable variation is observed in the near-edge X-ray absorption fine structure (NEXAFS) spectra of amino acids. To unambiguously characterize the chemical origin of this variation, we have acquired the nitrogen 1s NEXAFS spectra of several amino acids and other model compounds and complemented these experimental measurements with ab initio calculations of isolated molecules and molecular clusters. The systematic differences observed between the zwitterionic and un-ionized forms of amino acids arise directly from the structural difference (-NH2 vs -NH3+), which leads to a change in the degree of Rydberg-valence mixing. Further change arises from quenching of this Rydberg character in the spectra of condensed amino acids. Ab initio calculations are used to explore the degree of Rydberg-valence mixing in the solid state.

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)0.000
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 score0.046
Threshold uncertainty score0.577

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)0.0000.000

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 head0.003
GPT teacher head0.190
Teacher spread0.187 · 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