An Electron Localization Function (ELF) Study of the 2-Norbornyl Cation
Bibliographic record
Abstract
Wave functions obtained at Becke3LYP, Becke3PW91, MP2, and QCISD levels of theory for the 2-norbornyl cation ( 1 ) are used in a topological analysis of the Becke−Edgecombe electron localization function (ELF) with the Silvi suite of programs. Partitioning of the molecular space of the cation into basins of attractors yields information on the shared valence basin interactions at the C1−C2−C6 face of 1 and other C s species in which the C1−C6 and C2−C6 distances are increased incrementally to 193.5 pm. At the Becke3LYP/cc-PVTZ//Becke3LYP/cc-PVTZ level, a single trisynaptic basin with a population of 0.83 electrons connects C1 and C2 to C6 in the optimized geometry where the C1/C2−C6 distances are 188.9 pm. When the C1/C2−C6 distances are increased by 4.5 pm to 193.5 pm, the shared trisynaptic basin splits into a monosynaptic basin at C6 with a population of 0.49 electrons and a disynaptic basin between C1 and C2 with a population of 2.75 electrons; and Δ E T is only 0.12 kcal mol -1 . Disynaptic basins with electron populations in the region of 0.5 electrons link C1−C6 and C2−C6 in the equilibrium optimized geometries of 1 obtained at the MP2, Becke3PW91, and QCISD levels (the C1/C2−C6 distances range from 182.5 to 184.6 pm). This is the case even when the large correlation-consistent basis set cc-PVTZ is used to obtain the wave functions. But these shared interactions are lost when the C1/C2−C6 distances are increased in the range of 8 pm. While the nature of the basins at the C1−C2−C6 face depends on the C1/C2−C6 distances and the basis set, on the whole, increases in energy only ranging up to 0.55 kcal mol -1 are found with large basis sets when the distances are increased by 4−8 pm. At the point where the shared valence interactions between C1/C2 and C6 are lost, there is no discontinuity in the calculated total energy. According to our ELF analysis the formation of 1 from the C s primary “open” cation involves a transfer of electrons from the valence basin of the double bond at C1−C2 to a basin at C6 The stabilization of 1 relative to the open primary cation results from an electrostatic interaction between a carbocation and the electrons of a carbon−carbon double 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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.006 | 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".