Probing the Electronic Manifold of MgCl with Millimeter-Wave Spectroscopy and Theory: (3) <sup>2</sup> Σ <sup>+</sup> and (4) <sup>2</sup> Σ <sup>+</sup> States
Bibliographic record
Abstract
The millimeter/submillimeter spectrum of magnesium chloride (MgCl) has been observed in two new electronic excited states, (3) 2 Σ + and (4) 2 Σ +, using direct absorption methods. The molecule was synthesized in a mixture of Cl 2, argon, and magnesium vapor. For the (3) 2 Σ + state, multiple rotational transitions were measured in the v = 0 level for all six isotopologues ( 24 Mg 35 Cl, 24 Mg 37 Cl, 25 Mg 35 Cl, 25 Mg 37 Cl, 26 Mg 35 Cl, and 26 Mg 37 Cl), as well as up to v = 13 for 24 Mg 35 Cl. For the (4) 2 Σ + state, less intense spectra were recorded for 24 Mg 35 Cl ( v = 0–2). Equilibrium rotational parameters were determined for both states for 24 Mg 35 Cl, as well as rotational constants and 25 Mg hyperfine parameters for the other isotopologues. A perturbation was observed between rotational levels of the two states due to an avoided crossing. Computations were also carried out at the CASPT2 and MRCISD+Q levels, and the resulting bond lengths for (3) 2 Σ + and (4) 2 Σ + states agree well with the experimental values of r e = 2.536 and 2.361 Å. The computations show that the (3) 2 Σ + state has a double-well potential; however, the state behaves as a single well with unperturbed vibrational levels up to v = 13 due to nonadiabatic interactions with the (4) 2 Σ + state.
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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) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.004 |
| 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; both teacher heads agree on what is shown here.
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".