The molecular structures and spectroscopic properties of the ground state and the first excited state of pVP

Abstract

P-vinylphenol (pVP) is a common building block of a large number of fluorescent protein chromophores. Theoretical investigation employed TD-DFT calculation has been carried out on pVP molecule to reveal the structural properties that influence the absorption and fluorescence. The molecular structures of the first excited state (S-1) as well as the ground state (S-0) have been optimized. Based on these structures, the absorption spectra are simulated using the Franck-Condon factors and displaced-distorted harmonic oscillator model. The result agrees well with the reported experiment data. It's also found that the S-0 -> S-1 transition is a significant pi -> pi* transition. Besides the pi electrons on the benzene ring, the pi electron together with the lone pair electron on hydroxyl group takes parts in the transition. Therefore the absorption of pVP would be modulated not only by the isomerization but also by the intermolecular hydrogen bond. (C) 2017 Elsevier B.V. All rights reserved.