Evaluating excited state atomic polarizabilities of chromophores
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Published version
Author(s)
Heid, Esther
Hunt, Patricia A
Schroeder, Christian
Type
Journal Article
Abstract
Ground and excited state dipoles and polarizabilities of the chromophores N-methyl-6-oxyquinolinium betaine (MQ) and coumarin 153 (C153) in solution have been evaluated using time-dependent density functional theory (TD-DFT). A method for determining the atomic polarizabilities has been developed; the molecular dipole has been decomposed into atomic charge transfer and polarizability terms, and variation in the presence of an electric field has been used to evaluate atomic polarizabilities. On excitation, MQ undergoes very site-specific changes in polarizability while C153 shows significantly less variation. We also conclude that MQ cannot be adequately described by standard atomic polarizabilities based on atomic number and hybridization state. Changes in the molecular polarizability of MQ (on excitation) are not representative of the local site-specific changes in atomic polarizability, thus the overall molecular polarizability ratio Image ID:c7cp08549d-t1.gif does not provide a good approximation for local atom-specific polarizability changes on excitation. Accurate excited state force fields are needed for computer simulation of solvation dynamics. The chromophores considered in this study are often used as molecular probes. The methods and data reported here can be used for the construction of polarizable ground and excited state force fields. Atomic and molecular polarizabilities (ground and excited states) have been evaluated over a range of functionals and basis sets. Different mechanisms for including solvation effects have been examined; using a polarizable continuum model, explicit solvation and via sampling of clusters extracted from a MD simulation. A range of different solvents have also been considered.
Date Issued
2018-04-07
Date Acceptance
2018-03-05
Citation
Physical Chemistry Chemical Physics, 2018, 20 (13), pp.8554-8563
ISSN
1463-9076
Publisher
Royal Society of Chemistry
Start Page
8554
End Page
8563
Journal / Book Title
Physical Chemistry Chemical Physics
Volume
20
Issue
13
Copyright Statement
© 2018 Royal Society of Chemistry. This article is licensed under a Creative Commons Attribution 3.0 Unported Licence (https://creativecommons.org/licenses/by/3.0/).
Identifier
http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000428779700018&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=1ba7043ffcc86c417c072aa74d649202
Subjects
Science & Technology
Physical Sciences
Chemistry, Physical
Physics, Atomic, Molecular & Chemical
Chemistry
Physics
SOLUTE ELECTRONIC POLARIZABILITY
PHOTOSYNTHETIC PURPLE BACTERIA
MOLECULAR-DYNAMICS SIMULATIONS
CONTINUUM SOLVATION MODELS
TIME-RESOLVED FLUORESCENCE
LIGHT-HARVESTING ANTENNAS
DENSITY-FUNCTIONAL THEORY
STARK SPECTROSCOPY
IONIC LIQUIDS
COUMARIN 153
Publication Status
Published
Date Publish Online
2018-03-06