Conical shape fluctuations determine therate of ion-evaporation and the emitted cluster-size distribution from multiple-charged droplets
Bibliographic record
Abstract
The ion-evaporation mechanism (IEM) is perceived to be a major pathway for disintegration of multiple-ion charged droplets found in atmospheric and sprayed aerosols. However, the precise mechanism of IEM and the range of its validity have not been established yet despite its broad use in mass spectrometry and atmospheric chemistry over past half century. Here we present direct computational evidence of the mechanism by performing a systematic study over several kosmotropic and chaotropic ions. We find that in the parent droplet multiple kosmotropic ions are buried deeper below the droplet surface than chaotropic ions. This differentiation in the ion location is only captured by a polarizable model. We demonstrate that the emitted cluster-size distribution is determined by dynamic conical deformations and not from the equilibrium ion-depth within the parent droplet as the IEM models assume. We present critical factors that determine the cluster-size distribution such as the charge sign asymmetry that have not been considered in models and in experiments. We argue that the existing IEM analytical models do not establish a clear difference between IEM and Rayleigh fission.We propose a shift in the existing view for IEM from the equilibrium properties of the parent droplet to the chemistry in the conical shape fluctuations that lead to a single solvated-ion emission. Consequently, chemistry in the conical fluctuations may also be a key element to explain charge states of macromolecules in mass spectrometry and may have potential applications in catalysis.
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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 | 0.001 |
| 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 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 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".