Transient absorption, femtosecond dynamics, vibrational coherence and molecular modelling of the photoisomerization of N-salicylidene-o-aminophenol in solution.

This article presents a study of the excited state relaxation dynamics N-salycylidene-o-aminophenol (SOAP) in ethanol solution. Femtosecond transient absorption (TA) spectroscopy and theoretical calculations are used combination to establish mechanism type molecular species involved accompanying phototransformations. TA spectra show that upon photoexcitation two SOAP tautomers (E-enol Z-keto) interconvert by ESIPT. The molecule can subsequently isomerize E-keto form SOAP. An intriguing observation is this compound modulations signal at stimulated emission spectral range. It found these due coherence ensemble molecules whose evolution over time represents moving wave packet. After Fourier transform modulations, characteristic frequencies identified. These referred corresponding vibrational modes their nature elucidated DFT quantum chemical calculations. obtained experimental data reveal vibronic coupling between ground vibrations along potential surface first initial moment right after excitation. characterize starting point toward Z-E isomerization keto provides comprehensive picture dynamic processes taking place compound, which might enable control various channels.