Hydrogen Adsorption and Diffusion in <i>p</i>‐<i>tert</i>‐Butylcalix[4]arene: An Experimental and Molecular Simulation Study
Bibliographic record
Abstract
Experimental adsorption isotherms were measured and computer simulations were performed to determine the nature of the H(2) gas uptake in the low-density p-tert-butylcalix[4]arene (tBC) phase. (1)H NMR peak intensity measurements for pressures up to 175 bar were used to determine the H(2) adsorption isotherm. Weak surface adsorption (up to ≈2 mass % H(2) ) and stronger adsorption (not exceeding 0.25 mass % or one H(2) per calixarene bowl) inside the calixarene phase were detected. The latter type of adsorbed H(2) molecule has restricted motion and shows a reversible gas adsorption/desorption cycle. Pulsed field gradient (PFG) NMR pressurization/depressurization measurements were performed to study the diffusion of H(2) in the calixarene phases. Direct adsorption isotherms by exposure of the calixarene phase to pressures of H(2) gas to ≈60 bar are also presented, and show a maximum H(2) adsorption of 0.4 H(2) per calixarene bowl. Adsorption isotherms of H(2) in bulk tBC have been simulated using grand canonical Monte Carlo calculations in a rigid tBC framework, and yield adsorptions of ≈1 H(2) per calixarene bowl at saturation. Classical molecular dynamics simulations with a fully flexible calixarene molecular force field are used to determine the guest distribution and inclusion energy of the H(2) in the solid with different loadings.
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 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".