A ‘bottom up’, ab initio computational approach to understanding fundamental photophysical processes in nitrogen containing heterocycles, DNA bases and base pairs

Barbara Marchetti, T N V Karsili, Michael N R Ashfold, Wolfgang Domcke

Research output: Contribution to journalArticle (Academic Journal)

46 Citations (Scopus)
446 Downloads (Pure)

Abstract

The availability of non-radiative decay mechanisms by which photoexcited molecules can revert to their ground electronic state, without experiencing potentially deleterious chemical transformation, is fundamental to molecular photostability. This Perspective Article combines results of new ab initio electronic structure calculations and prior experimental data in an effort to systematise trends in the non-radiative decay following UV excitation of selected families of heterocyclic molecules. We start with the prototypical uni- and bicyclic molecules phenol and indole, and explore the structural and photophysical consequences of incorporating progressively more nitrogen atoms within the respective ring structures en route to the DNA bases thymine, cytosine, adenine and guanine. For each of the latter, we identify low energy non-radiative decay pathways via conical intersections with the ground state potential energy surface accessed by out-of-plane ring deformations. This is followed by summary descriptions and illustrations of selected rival (electron driven H atom transfer) non-radiative excited state decay processes that demand consideration once the nucleobases are merely components in larger biomolecular systems like nucleosides, and both individual and stacked base-pairs.
Original languageEnglish
Pages (from-to)20007-20027
Number of pages22
JournalPhysical Chemistry Chemical Physics
Volume18
Issue number30
Early online date8 Mar 2016
DOIs
Publication statusPublished - 14 Aug 2016

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