Double Cation Formation from the Photo-Fragmentation of the <i>closo</i>-Carboranes
Bibliographic record
Abstract
Abstract Time-of-flight mass analysis with multi-stop coincidence detection has been used to study the multi-cation ionic fragmentation via fission of three isomeric carborane icosahedral cage compounds closo -1,2-orthocarborane, closo -1,7-metacarborane, closo -1,12-paracarborane (C 2 B 10 H 12 ) following inner-shell excitation at or above the B 1s regime. Photoelectron-photoion-photoion coincidence (PEPIPICO) spectroscopy was used to study the dominant fission routes in the core level excitation regime. Series of ion pairs are identified, where asymmetric fission dominates, leading to ion pairs of different mass. The fragmentation yields and charge separation mass spectra of all three isomers are generally quite similar in that the ion pairs (H + , Y + ), (Y + , Y 11 + ), and (Y 3 + , Y 9 + ) dominate, where Y + denotes the mass region from B + to CH + . Slight differences are observed at the B 1s-threshold, where the H + and BH 2 + /CH + ion pairs dominate for ortho- and meta-carborane, while (Y + , Y 11 + ) ion pairs dominate the multi-photofragment ion yield of paracarborane. These similarities and distinct differences in charge separation are discussed by considering the energetics of these three major species of ion pairs, as well as charge distributions in closo -carboranes and charge distributions in the carborane cage. It is shown that product formation via charge separation is driven by electronic relaxation, so that the lowest energy products are not necessarily formed.
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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".