Molecular modeling of indole-based materials with efficient electron withdrawing moieties to enhance optical nonlinearity: Quantum chemical investigation
Bibliographic record
Abstract
Herein, a series of seven indole-based donor-π-acceptor (D-π-A) chromophores ( 3aiR and 3ai2 - 3ai8 ) was designed via strategic modification of the terminal acceptor moieties. Density functional theory (DFT) and time-dependent DFT (TD/DFT) calculations were executed at M06/6-311G(d,p) level. To investigate the optoelectronic properties of 3aiR and 3ai2 - 3ai8, various analyses were conducted, including UV-Visible, frontier molecular orbitals (FMO), density of states (DOS), transition density matrix (TDM), natural bond orbitals (NBOs), and nonlinear optical (NLO) properties. Among all the designed derivatives, 3ai6 exhibited the narrowest band gap (2.497 eV), the most significant redshift (478.907 nm), and the highest chemical reactivity, as indicated by its maximum softness value of 0.401 eV⁻ 1 . Moreover, DOS and TDM analyses further supported the charge delocalization observed in FMO analysis. The NBO analysis revealed significant hyperconjugative interactions and enhanced intramolecular charge transfer (ICT), contributing to the stability of the designed compounds. While all derivatives demonstrated promising NLO properties, 3ai6 exhibited the highest static first-order ( β total = 2.89×10 -28 cm⁴ statvolt⁻ 1 ) and second-order ( γ total = 2.32×10 -33 cm 5 statvolt⁻ 1 ) hyperpolarizability values. The dynamic first-order hyperpolarizability β(−ω;ω,0) EOPE, shows enhanced values at 532 nm , with 3ai5 exhibiting the maximum β total of 599 × 10⁻ 2 ⁸ statvolt⁻ 1 cm⁴. Similarly, the second harmonic generation (SHG) (−2ω;ω,ω) is more pronounced at this shorter wavelength. In contrast, the second-order hyperpolarizability γ(−ω;ω,0,0) shows slightly higher values at 532 nm , peaking at -421000 × 10⁻ 33 statvolt⁻ 1 cm 5 for 3ai8 , indicating a frequency-dependent NLO response. These findings provide crucial insights into the structure-property relationships of indole-based materials, facilitating further advancements in the NLO domain.
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 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) | 0.001 | 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 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".