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Record W2884026635 · doi:10.1063/1.5037443

Toward interactive scanning tunneling microscopy simulations of large-scale molecular systems in real time

2018· article· en· W2884026635 on OpenAlexafffund
Marc‐André Dubois, Xavier Bouju, Alain Rochefort

Bibliographic record

VenueJournal of Applied Physics · 2018
Typearticle
Languageen
FieldEngineering
TopicSurface Chemistry and Catalysis
Canadian institutionsPolytechnique MontréalRegroupement Québécois sur les Matériaux de Pointe
FundersNatural Sciences and Engineering Research Council of CanadaAgence Nationale de la RechercheCompute Canada
KeywordsScanning tunneling microscopeDelocalized electronLinear scaleRelaxation (psychology)van der Waals forceElectronic structureMolecular dynamicsDensity functional theoryStatistical physicsChemistryChemical physicsMaterials scienceMoleculeComputational chemistryNanotechnologyPhysics

Abstract

fetched live from OpenAlex

We have developed a simulation tool in which structural or chemical modifications of an adsorbed molecular layer can be interactively performed, and where structural relaxation and nearly real-time evaluation of a scanning tunneling microscopy (STM) image are considered. This approach is built from an optimized integration of the atomic superposition and electron delocalization molecular orbital theory (ASED-MO) to which a van der Waals correction term is added in conjunction with a non-linear optimization algorithm based on the Broyden-Fletcher-Goldfarb-Shanno method. This integrated approach provides reliable optimized geometries for adsorbed species on metallic surfaces in a reasonable time. Although we performed a major revision of the ASED-MO parameters, the proposed computational approach can accurately reproduce the geometries of a various amount of covalent molecules and weakly bonded complexes contained in two well-defined datasets. More importantly, the relaxation of adsorbed species on a metal surface leads to molecular geometries in good agreement with experimental and Density Functional Theory results. From this, the electronic structure obtained from ASED-MO is used to compute the STM image of the system nearly in real-time using the Tersoff-Hamann formalism. We developed a parallelization strategy that uses Graphics Processing Units to reduce the computing time of STM simulation by a factor of 30. Such improvements allow one to simulate STM images of large supramolecular arrangements and to investigate the influence of realistic local chemical or structural defects on metal surfaces.

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)0.002
Version: metacan-v3-hybrid-931329e0061cValidation status: machine_predicted_unvalidated
Candidate categoriesnone
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Simulation or modeling · Consensus signal: Simulation or modeling
GenreCandidate signal: Empirical · Consensus signal: none
Teacher disagreement score0.007
Threshold uncertainty score0.014

Distilled classifier scores by category (both heads)

CategoryCodexGemma
Metaresearch0.0010.002
Meta-epidemiology (narrow)0.0010.001
Meta-epidemiology (broad)0.0010.001
Bibliometrics0.0000.001
Science and technology studies0.0010.001
Scholarly communication0.0010.001
Open science0.0020.001
Research integrity0.0010.001
Insufficient payload (model declined to judge)0.0020.000

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 head0.008
GPT teacher head0.250
Teacher spread0.242 · 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 designSimulation or modeling
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

Citations3
Published2018
Admission routes2
Has abstractyes

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