Formation of Methyl Radicals from Decomposition of Methyl-Substituted Silanes over Tungsten and Tantalum Filament Surfaces
Bibliographic record
Abstract
The formation of methyl radical from the decomposition of four methyl-substituted silane molecules, including monomethylsilane (MMS), dimethylsilane (DMS), trimethylsilane (TriMS), and tetramethylsilane (TMS), over tungsten and tantalum filament surfaces has been systematically studied using vacuum ultraviolet laser ionization mass spectrometry. The methyl radical intensity increases with temperature for both filaments in the low-temperature region; however, beyond the optimum temperature, a gradual decrease in the methyl intensity was observed for MMS, DMS, and TriMS when using Ta, whereas the intensity reaches a plateau with W. This is due to the fact that Ta is more efficient in releasing surface-bound H and forming active sites, leading to the adsorption of methyl radicals on the metal surface in the high-temperature regions. The apparent activation energy for methyl radical formation from the dissociation of MMS, DMS, TriMS, and TMS molecules on both W and Ta filaments increases with the increasing number of methyl substitution. The dissociation process is believed to be initiated by the Si-H bond cleavage and followed by Si-CH3 bond breaking. The obtained low activation energy values for methyl radical formation in the range of 51.1-84.7 kJ·mol(-1) suggest that the ejection of CH3 radicals is accompanied by the formation of a Si moiety bound to the metal surface. Overall, TMS produces the least number of methyl radicals on both filaments with the highest activation energy. The numbers of methyl radicals produced when using MMS, DMS, and TriMS are similar, but MMS gives the lowest activation energy.
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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 | 0.001 | 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 | 0.001 |
| 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".