Solvation of Hydrogen Sulfide in Liquid Water and at the Water–Vapor Interface Using a Polarizable Force Field
Bibliographic record
Abstract
Molecular dynamics (MD) simulations using the Drude polarizable force field are used to study the solution and interfacial properties of hydrogen sulfide (H2S) in water. Pairwise H2O-H2S Lennard-Jones interactions were optimized to the experimental H2S gas solubility at 298 K. These parameters yield hydration free energies and diffusion coefficients for H2S that are in good agreement with the experiment over 273-323 K and 298-368 K, respectively. H2S is sparingly soluble in water, with a ΔG(hydr)° of -0.5 kcal mol(-1). The free energy perturbation (FEP) calculations and analysis of the radial distribution functions show that H2S has limited hydrogen bonding and electrostatic interactions with the water solvent and generally behaves like a hydrophobic solute. These features were confirmed by ab initio MD simulations. Umbrella sampling simulations were used to calculate the free energy profile of the transition of H2S across the water-vapor interface, which showed that H2S has a sizable surface excess, with a ΔG(surf) of 1.3 kcal mol(-1). This high surface excess is consistent with our calculations of the surface tension, which decreases to 20 dyn cm(-1) under high densities of H2S (g). The dipole moment of H2S increases from its gas phase value of 0.98 to 1.25 D in bulk water as it moves across the interface. Adsorbed H2S tends to be oriented perpendicular to the interface, with the sulfur atom pointing toward the vapor phase.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 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".