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Record W2009651317 · doi:10.1021/ct900029d

Integrated Continuum Dielectric Approaches To Treat Molecular Polarizability and the Condensed Phase: Refractive Index and Implicit Solvation

2009· article· en· W2009651317 on OpenAlexaff
Jean‐François Truchon, Anthony Nicholls, Benoı̂t Roux, Radu Iftimie, Christopher I. Bayly

Bibliographic record

VenueJournal of Chemical Theory and Computation · 2009
Typearticle
Languageen
FieldPhysics and Astronomy
TopicSpectroscopy and Quantum Chemical Studies
Canadian institutionsUniversité de Montréal
FundersNational Institute of General Medical Sciences
KeywordsPolarizabilityDielectricRefractive indexSolvationIsotropyAnisotropyPolarization (electrochemistry)ChemistryAb initioComputational chemistryMolecular physicsCondensed matter physicsMoleculeChemical physicsPhysicsOpticsQuantum mechanicsPhysical chemistryOrganic chemistry

Abstract

fetched live from OpenAlex

The idea of using a dielectric continuum inside a molecule to accurately model molecular polarizability is extended to include a larger spectrum of bioorganic molecules and the condensed phase. Atomic polarization radii and an internal dielectric (ε in ) were fitted to reproduce ab initio B3LYP/aug-cc-pVTZ polarizability tensors taken from a data set of 707 molecules. The average unsigned error on the isotropic polarizability and anisotropy are 2.6% and 5.2%, respectively. It is shown that usual Poisson−Boltzmann contact radii and a low internal dielectric are not appropriate and require major revision. To account for the anisotropy of polarizability, the internal dielectric (ε in ) constant needs to be larger than 6.0. Reinterpreting the theoretical link between ε in and the experimental refractive index ( n ), this study shows, with a set of 23 organic molecules spanning the entire range of n, that even with ε in = 24 the obtained refractive indices can correlate well with experiment (slope of 1.00, intercept of 0.05, and R = 0.95). The novel methodology used here to calculate a macroscopic-like refractive index shows that the application of the EPIC parametrization to condensed phase leads to suitable behavior. Although the primary goal in developing EPIC was to include polarizability in explicit solvent calculations, we also extend the model to work with implicit solvent. This requires the use of a 3-zone smooth dielectric function to transition from the polarization dielectric inside the molecules to the dielectric continuum of the solvent. The parametrization and validation of this model are performed against 485 experimental free energies of hydration. Using 8 solvent cavity atomic radii and a single surface tension an average unsigned error of 1.1 kal/mol and a correlation coefficient of 0.9 are obtained, validating the use of the EPIC model in the condensed phase.

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 categoriesnone
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Bench or experimental · Consensus signal: none
GenreCandidate signal: Empirical · Consensus signal: Empirical
Teacher disagreement score0.504
Threshold uncertainty score0.264

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 head0.017
GPT teacher head0.276
Teacher spread0.259 · 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.

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

Citations20
Published2009
Admission routes1
Has abstractyes

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