Two-dimensional IR-visible sum frequency generation spectroscopy: a unique probe of surface electronic states at buried interfaces
Bibliographic record
Abstract
Interfacial electronic states and charge transfer play an important role in many organic devices, but it has been technically challenging to probe surface electronic states under ambient conditions or at buried interfaces. Developments in two-dimensional (2D) IR-visible sum frequency generation (SFG) spectroscopy have made it possible to study the optical and electronic properties of organic molecules located at a buried interface. We present studies of poly[2- methoxy, 5-ethyl (2'-hexyloxy) para-phenylenevinylene] (MEH-PPV) surfaces using 2D SFG. Surface SFG electronic spectra were obtained by scanning the frequencies of both incident visible and IR beams, and used to study the electronic transitions associated with the C-C stretching of benzene rings. Assuming an oligomer model and a Gaussian conjugation-length distribution, the average conjugation lengths were estimated to be 5.8 monomer units at the MEHPPV/ solid interface and 5.1 monomer units at the air/polymer interface.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot 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.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
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.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
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".