High-Pressure <sup>129</sup>Xe NMR Study of Xenon Confined in the Nanochannels of Solid (±)-[Co(en)<sub>3</sub>]Cl<sub>3</sub>
Bibliographic record
Abstract
High-pressure 129 Xe NMR measurements were carried out on dehydrated (±)-[Co(en) 3 ]Cl 3 to investigate the pore size as well as the local structure about the confined xenon atoms. At xenon gas pressures of 0.3 MPa, the xenon chemical shift was orientation dependent, exhibiting an axially symmetric powder pattern with δ 11 = 280 ppm and δ 22 = δ 33 = 180 ppm. Proton to 129 Xe cross-polarization (CP) experiments selectively enhanced the portion of the powder pattern corresponding to δ 22 = δ 33 = δ ⊥, confirming that the unique component of the chemical shift tensor, δ 11 = δ ∥, lies along the pore axis. The isotropic chemical shift δ iso at the zero pressure limit was found to be 212 ppm, and suggested a pore diameter of approximately 0.47 nm. This agrees well with the diameter of 0.44 nm estimated from the crystal structure. On increasing the pressure to 6.5 MPa, δ ⊥ increased from 180 to 220 ppm, whereas δ ∥ was found to be almost independent of pressure. The increase in δ ⊥ with pressure is attributed to Xe−Xe interactions. The paramagnetic shift in the xenon chemical tensor component perpendicular to the nanochannels with increasing pressure is in accord with the recent theoretical predictions of Jameson and de Dios ( J. Chem. Phys. 2002, 116, 3805) and Jameson ( J. Chem. Phys. 2002, 116, 8912).
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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 | 0.000 |
| 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) | 0.001 | 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".