Investigation of Aggregation Induced Emission Mechanism of Tetrabenzoheptafulvalene Derivative by Spin‐Flip Time‐Dependent Density Functional Theory (SF‐TDDFT)
Bibliographic record
Abstract
Abstract This study explores the mechanism of aggregation‐induced emission (AIE) in the tetrabenzoheptafulvalene derivative, 10,10′,11,11′‐tetrahydro‐5,5′‐bidibenzo[a,d][7]annulenylidene (abbreviated as THBDBA) in tetrahydrofuran (THF) solution. THBDBA is AIE‐active because in THF solution, it emits significantly less emission (or almost non‐emissive) and the fluorescence quantum yield increases by 230 times in aggregate state. We adopted spin‐flip time‐dependent density functional theory (SF‐TDDFT), widely acknowledged for its ability to locate the conical intersection (CI) in medium to large‐sized molecules (due to its balanced and reliable description of both ground and excited states and ability to capture double excitation and multireference characters at low computational cost). The functional used is long‐range corrected ωPBEh (i. e., LRC‐ωPBEh). The strategies used are the excited state deactivation processes by taking into account the S 1 /S 0 surface crossing, referred to as the ‘minimum energy conical intersection’ (MECI). Reduction of oscillator strength near the minimum energy gap (MEG) structure or CI is also another parameter used to study fluorescence quenching. For the monomer (i. e., in solution), our findings reveal a significant reduction in oscillator strength ( f ) for de‐excitation near the MEG structure and CI, which led us to conclude that in solution, the flapping motion of the phenyl rings plays a vital role to reach the CI. In a smaller scale, a dimer system was chosen to represent the aggregate state. The higher energy gap as well as higher f‐ value at MEG structure with just the model dimer system indicates that in the actual aggregate (or the crystal) the MECI might be absent. This is because in the aggregate the flapping motion of the phenyl rings will be highly restricted (because of the steric and electrostatic confinements by a large number of monomers from all sides), thereby favoring radiative transitions for energy dissipation. This study consequently elucidates the AIE mechanism of the chosen tetrabenzoheptafulvalene derivative, shedding light on its photophysical properties.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| 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; 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".