The electronic spectrum of germanium methylidyne (GeCH), the prototypical organogermanium compound
Bibliographic record
Abstract
The à 2Σ+–X̃ 2Πi electronic transition of jet-cooled germanium methylidyne has been recorded in the 730–555 nm region by laser-induced fluorescence techniques. The radical was produced in a pulsed electric discharge using tetramethylgermane as the precursor. The band system consists of perpendicular and vibronically induced parallel bands with upper state frequencies of ν2′=638/497 cm−1 and ν3′=990/952 cm−1 for GeCH/GeCD. The Σ+2–2Π3/2 components of the 000 bands of GeCH and GeCD and the 201 band of GeCH have been recorded with sufficient resolution to assign the transitions of the Ge70, Ge72, Ge74, and Ge76 isotopomers. The rotational constants of the various hydrogen and germanium isotopomers were used to derive the following molecular structures: r0″(Ge–C)=1.775 79(21) Å, r0″(C–H)=1.0673(12) Å, r0′(Ge–C)=1.673 66(8) Å, and r0′(C–H)=1.0589(5) Å. The ground state germanium–carbon bond length is typical for a Ge=C double bond, but in the excited state it corresponds to a triple bond. This is a consequence of promotion of an electron from a nonbonding σ orbital to a π bonding orbital to form the …σ1π4(2Σ+) excited state. In this study we provide the first experimental value for the length of the germanium–carbon triple bond.
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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) | 0.002 | 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".