Journal article
Evaluating excited state atomic polarizabilities of chromophores
Physical chemistry chemical physics : PCCP, Vol.20(13), pp.8554-8563
2018
Handle:
https://hdl.handle.net/2376/101765
PMID: 29542743
Abstract
Ground and excited state dipoles and polarizabilities of the chromophoresN-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 ratiodoes 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 andviasampling of clusters extracted from a MD simulation. A range of different solvents have also been considered.
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Details
- Title
- Evaluating excited state atomic polarizabilities of chromophores
- Creators
- Esther Heid - University of Vienna, Faculty of Chemistry, Department of Computational Biological Chemistry, A-1090 Vienna, AustriaPatricia A Hunt - Department of Chemistry, Imperial College London, London, UKChristian Schröder - University of Vienna, Faculty of Chemistry, Department of Computational Biological Chemistry, A-1090 Vienna, Austria
- Publication Details
- Physical chemistry chemical physics : PCCP, Vol.20(13), pp.8554-8563
- Identifiers
- 99900546693701842
- Language
- English
- Resource Type
- Journal article