Dr. Ali Hassanali e Dr. Uriel Nicolas Morzan ICTP Trieste (Abdus Salam International Centre for Theoretical Physics) 11:30 am, Room II - Department of Industrial Chemistry "Toso Montanari"
Date: 16 MAY 2022 from 11:30 to 12:30
Abstract
Conventional chemical wisdom associates fluorescence in biological matter with the aromatics or more generally conjugated systems. Recent experiments [1-6] suggest that it is possible to observe both excitation in the near-UV and subsequent fluorescence in the visible without the presence of these chemical moieties. The origins of this phenomenon remains poorly understood. In this talk, we will provide an overview of the computational and theoretical work over the last couple of years aimed at unraveling the spectroscopic origins of this phenomenon. Using a variety of techniques including ab initio ground-state molecular dynamics, static excited-state absorption spectra and non-adiabatic molecular dynamics simulations, we demonstrate that the stiffening of specific vibrational modes offers a mechanism that can lead to trapping on the excited state thereby enhancing the possibility of fluorescence. Our findings are corroborated with experimental fluorescence measurements on amyloid aggregates and amino-acid crystal structures relevant for neurodegenerative diseases. Non-aromatic fluorescence may offer novel diagnostic tools paving the way for the development of non-invasive and non-toxic probes of complex biological processes.
