{'fraction_non_alphanumeric': 0.029891304347826088, 'fraction_numerical': 0.001358695652173913, 'mean_word_length': 6.047846889952153, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Buried liquid interfaces as a form of chemistry in confinement: the case of 4-dimethylaminobenzonitrile (DMABN) at the silica-aqueous interface.

Time-resolved fluorescence emission and resonance enhanced second harmonic generation (SHG) spec-tra were collected from 4-dimethylaminobenzonitrile (DMABN) adsorbed to the aqueous-silica interface in order to identify how strongly associating solvent-substrate interactions change DMABN's photoisomerization properties. In bulk polar solution, DMABN forms an excited twisted intramolecular charge transfer (TICT) state that emits with a distinctive, solvatochromic fluo-rescent signature. At the silica-aqueous interface, the TICT fluorescence disappears, similar to DMABN's behavior in nonpolar environments. SHG spectra confirm that the interface is, in fact, polar, and DMABN's unusual fluorescence emis-sion acquired from the interface is attributed to strong hydrogen bonding associations between the water molecules and the silica surface that prevent adsorbate isomerization. Additionally, SHG spectra show a strong resonance at long wavelengths that is unexpected based on bulk absorbance spectra and selection rules for nonlinear hyperpolarizabilities. Using both Zerner's INDO semi-empirical and TD-DFT calculations, this spectroscopic behavior is attributed to a combination of strong electric fields present at the aqueous-silica interface and surface induced changes to DMABN's ground state molec-ular structure.