Isomerisation Dynamics of a Thiacarbocyanine Dye in Different Electronic States and in Different Classes of Solvents

Vauthey, Eric

doi:10.1016/0301-0104(95)00135-B

Scientific article

English

Isomerisation Dynamics of a Thiacarbocyanine Dye in Different Electronic States and in Different Classes of Solvents

Contributors

Vauthey, Eric

Published in

Chemical physics, vol. 196, no. 3, p. 569-582

Publication date

1995

Abstract

A study of the isomerisation dynamics of 3,3'-diethylthiacarbocyanine in the excited state in alkanenitriles as well as in the ground state in both alkanenitriles and n-alcohols, using ps transient grating spectroscopy and flash photolysis is reported. The intrinsic activation energy for isomerisation has been determined from isoviscosity plots. In the ground state, the activation energy amounts to 12.9 kcal/mol in both nitriles and alcohols, while it is equal to 3.0 kcal/mol in the excited state. The reduced isomerisation rate constant shows a fractional dependence on the solvent viscosity, with a fractional exponent α of 0.20 and 0.38 for the ground state isomerisation in alcohols and nitriles and of 0.65 for the excited state isomerisation. The data have been analysed within the framework of the Kramers theory using different models for friction. The best agreement was obtained with the Grote-Hynes model, which takes into account the frequency dependence of the friction. The solvent dependence of α for the ground state isomerisation is accounted for by a different average value of the infinite frequency shear modulus in alcohols and nitriles. The barrier height dependence of α is explained by a decrease of the barrier's top frequency by going from the ground to the excited state.

UNIGE affiliation entities

Faculté des sciences / Section de chimie et biochimie / Département de chimie physique

UNIGE research groups

Groupe Vauthey

Citation (ISO format)

VAUTHEY, Eric. Isomerisation Dynamics of a Thiacarbocyanine Dye in Different Electronic States and in Different Classes of Solvents. In: Chemical physics, 1995, vol. 196, n° 3, p. 569–582. doi: 10.1016/0301-0104(95)00135-B

Article (Published version)

Identifiers

PID : unige:2990
DOI : 10.1016/0301-0104(95)00135-B

Additional URL for this publication

http://www.sciencedirect.com/science?_ob=MImg&_imagekey=B6TFM-3YB9XK2-3P-3&_cdi=5230&_orig=browse&_coverDate=07%2F01%2F1995&_sk=998039996&view=c&wchp=dGLbVlz-lSztA&_acct=C000043220&_version=1&_userid=779890&md5=6fd2818242c2dc69de2f6e4565291841&ie=f.pdf

Journal ISSN

0301-0104

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492downloads

Creation

21/09/2009 16:11:09

First validation

21/09/2009 16:11:09

Update

14/03/2023 15:12:41

Status update

14/03/2023 15:12:41

Last indexation

29/10/2024 12:07:06

Isomerisation Dynamics of a Thiacarbocyanine Dye in Different Electronic States and in Different Classes of Solvents

Contributors

Published in

Publication date

Abstract

UNIGE affiliation entities

UNIGE research groups

Citation (ISO format)

Main files (1)

Identifiers

Additional URL for this publication

Journal ISSN

Technical informations

Creation

First validation

Update

Status update

Last indexation