The Structure of the Protonated Adenine Dimer by Infrared Multiple Photon Dissociation Spectroscopy and Electronic Structure Calculations
Bibliographic record
Abstract
The infrared multiple photon dissociation (IRMPD) spectrum of electrosprayed adenine proton-bound dimers were recorded in the gas-phase inside the cell of a Fourier transform ion cyclotron resonance spectrometer coupled to a tunable optical parametric oscillator/amplifier infrared laser. While gas-phase B3LYP/6-31+G(d,p) calculations indicate that the four lowest isomers are essentially isoenergetic, comparisons of the experimental and predicted IR spectra suggest that only two of the four isomers are observed in the experiment. However, computed solvation effects, as modeled using both a polarizable continuum model and microsolvation with five explicit water molecules, preferentially stabilize these two observed isomers, consistent with the interpretation of the IRMPD spectra. This work shows that for these small species the solvent-phase structure is preserved. It also demonstrates the potential danger of using gas-phase calculations to predict the structures of gaseous ions born in solution, such as those from an electrospray source.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot 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.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".