Modeling the temperature dependence of the fluorescence properties of Indole in aqueous solution

Cheng Giuseppe Chen; Andrea Amadei; Marco D'Abramo

doi:10.1016/j.saa.2024.124096

Modeling the temperature dependence of the fluorescence properties of Indole in aqueous solution

Spectrochim Acta A Mol Biomol Spectrosc. 2024 May 15:313:124096. doi: 10.1016/j.saa.2024.124096. Epub 2024 Feb 28.

Authors

Cheng Giuseppe Chen¹, Andrea Amadei², Marco D'Abramo³

Affiliations

¹ Department of Chemistry, Sapienza University of Rome, Piazzale Aldo Moro, 5, Rome, 00185, Italy.
² Department of Technological and Chemical Sciences, Tor Vergata University of Rome, Via della Ricerca Scientifica, 1, Rome, 00133, Italy. Electronic address: andrea.amadei@uniroma2.it.
³ Department of Chemistry, Sapienza University of Rome, Piazzale Aldo Moro, 5, Rome, 00185, Italy. Electronic address: marco.dabramo@uniroma1.it.

PMID: 38442616
DOI: 10.1016/j.saa.2024.124096

Abstract

In a recent paper, we proposed a scheme to describe the relaxation mechanism of the excited Indole in aqueous solution, involving the fluctuations among the diabatic electronic states ¹L_b, ¹L_a and ¹πσ^∗. Such a theoretical and computational model reproduced accurately the available experimental data at room temperature. Following these results, in the present work, we model the complex temperature dependence of the fluorescence properties of Indole in aqueous solution, with results further validating the proposed relaxation scheme. This scheme is able to explain the temperature effects on the fluorescence behavior indicating the water fluctuations as the main cause of (i) the stabilization of the dark state (¹πσ^∗) and (ii) the increase in temperature of the kinetics of the irreversible transition towards such a state.

Keywords: Excited state dynamics; Fluorescence; Indole; MD-PMM; Temperature dependence.