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Simulations of the absorption and fluorescence of indole in aqueous solution and at a nonpolar/polar interface

Öhrn, Anders LU and Karlström, Gunnar LU (2007) In The Journal of Physical Chemistry Part A: Molecules, Spectroscopy, Kinetics, Environment and General Theory 111(42). p.10468-10477
Abstract
Theoretical results are presented on the absorption and fluorescence of indole in aqueous solution as well as at the air/water surface. We use a combined quantum chemical statistical mechanical model with explicit solvent. An approximate ab initio complete active space self-consistent field description of the indole molecule is used, coupled to a discrete polarizable water medium. From the bulk simulations, strong support is found for the interchange mechanism, which explains the unusual solvent shift of the fluorescence of indole or tryptophan in a polar surrounding by a solvent induced switch of the fluorescing state. Two mechanisms are given to explain the different shifts for indole at the interface. First, a dielectric depletion... (More)
Theoretical results are presented on the absorption and fluorescence of indole in aqueous solution as well as at the air/water surface. We use a combined quantum chemical statistical mechanical model with explicit solvent. An approximate ab initio complete active space self-consistent field description of the indole molecule is used, coupled to a discrete polarizable water medium. From the bulk simulations, strong support is found for the interchange mechanism, which explains the unusual solvent shift of the fluorescence of indole or tryptophan in a polar surrounding by a solvent induced switch of the fluorescing state. Two mechanisms are given to explain the different shifts for indole at the interface. First, a dielectric depletion effect, which is expected from the reduction of the amount of polar media. Second, an interface-specific effect, which derives from the stronger hydrogen bond formation at the surface. The latter effect acts to increase the shift for both absorption and emission at the surface as compared to the bulk. From these results, the intrinsic probe photophysics of tryptophan in proteins is discussed in terms of the properties of the protein/solvent interface and the orientation of the amino acid. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
The Journal of Physical Chemistry Part A: Molecules, Spectroscopy, Kinetics, Environment and General Theory
volume
111
issue
42
pages
10468 - 10477
publisher
The American Chemical Society
external identifiers
  • wos:000251947900005
  • scopus:35948953637
ISSN
1520-5215
DOI
10.1021/jp0744477
language
English
LU publication?
yes
id
ae94dfde-09f1-4922-981f-07144c045a20 (old id 1408374)
date added to LUP
2009-06-02 09:14:39
date last changed
2017-01-01 07:09:30
@article{ae94dfde-09f1-4922-981f-07144c045a20,
  abstract     = {Theoretical results are presented on the absorption and fluorescence of indole in aqueous solution as well as at the air/water surface. We use a combined quantum chemical statistical mechanical model with explicit solvent. An approximate ab initio complete active space self-consistent field description of the indole molecule is used, coupled to a discrete polarizable water medium. From the bulk simulations, strong support is found for the interchange mechanism, which explains the unusual solvent shift of the fluorescence of indole or tryptophan in a polar surrounding by a solvent induced switch of the fluorescing state. Two mechanisms are given to explain the different shifts for indole at the interface. First, a dielectric depletion effect, which is expected from the reduction of the amount of polar media. Second, an interface-specific effect, which derives from the stronger hydrogen bond formation at the surface. The latter effect acts to increase the shift for both absorption and emission at the surface as compared to the bulk. From these results, the intrinsic probe photophysics of tryptophan in proteins is discussed in terms of the properties of the protein/solvent interface and the orientation of the amino acid.},
  author       = {Öhrn, Anders and Karlström, Gunnar},
  issn         = {1520-5215},
  language     = {eng},
  number       = {42},
  pages        = {10468--10477},
  publisher    = {The American Chemical Society},
  series       = {The Journal of Physical Chemistry Part A: Molecules, Spectroscopy, Kinetics, Environment and General Theory},
  title        = {Simulations of the absorption and fluorescence of indole in aqueous solution and at a nonpolar/polar interface},
  url          = {http://dx.doi.org/10.1021/jp0744477},
  volume       = {111},
  year         = {2007},
}