Low Density Interior in Supercooled Aqueous Nanodroplets Expels Ions to the Subsurface
Bibliographic record
Abstract
The interaction between water and ions within droplets plays a key role in the chemical reactivity of atmospheric and man-made aerosols. Here we report direct computational evidence that in supercooled aqueous nanodroplets <br>a lower density core of tetrahedrally coordinated water expels the Na+ ions to a denser and more disordered subsurface. In contrast, at room temperature, the radial distribution of a single Na+ ion in the droplet core <br>is nearly uniform. We analyze the spatial distribution of a single ion in terms of a new reference electrostatic model that we present here. The energy of the system in the analytical model is expressed as the sum of the electrostatic and surface energy of a deformable droplet. The model predicts that the ion is subject to a harmonic potential centered at the droplet's center of mass. We name this effect ``electrostatic confinement''.<br>The model's predictions are consistent with the simulation findings for a single Na+ ion at room temperature but not at supercooling. Because of the droplet's core organization at supercooling the distribution of multiple ions cannot be explained by the non-linear Poisson-Boltzmann equation.<br>Our study provides insight into the chemistry of atmospheric aerosols. We anticipate it to be the starting point for investigating the structure of supercooled electrosprayed droplets that are used to preserve the conformations of macromolecules originating from the bulk solution.<br>
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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 | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.004 | 0.002 |
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; both teacher heads agree on what is shown here.
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".