Restoring Charge Asymmetry in Continuum Electrostatics Calculations of Hydration Free Energies
Bibliographic record
Abstract
Implicit solvation models are symmetric with respect to charge inversion. On the other hand, explicit solvent simulations show significant asymmetry in hydration free energies with respect to charge reversal. It has not been obvious how implicit solvation models can be modified in a general way to address this serious shortcoming. We solve this problem by using the induced surface charge density (ISCD) obtained from a boundary element solution of the Poisson equation to derive a simple customized correction for the Born radius of each atom. This simple correction restores the charge asymmetry and reproduces the hydration free energies from free energy perturbation calculations with a high degree of fidelity. The induced surface charge density profile of an atom essentially provides a measure of the average preferred orientation of a water molecule in the first solvation shell, thereby allowing a proper assignment of the dielectric boundary. We refer to these modified radii as ISCD-corrected Born radii.
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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 | 0.000 |
| 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".