Table of Contents
Laser Chemistry
Volume 11, Issue 2, Pages 109-118

Picosecond Time Resolved Absorption Experiments of Iodine in Complexing Solvents

1Laboratoire de Spectroscopie Moléculaire et Cristalline, U.R.A.124-C.N.R.S., Talence Cedex 33405 , France
2Laboratoire de Photochimie et Photophysique Moléculaire, U.R.A.348-C.N.R.S., Talence Cedex 33405 , France
3Centre de Physique Moléculaire Optique et Hertzienne, U.R.A.283-C.N.R.S., Talence Cedex 33405, France
4Université de Bordeaux I, 351, Cours de la Libération, Talence Cedex 33405 , France

Accepted 2 May 1991

Copyright © 1991 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Transient absorption spectra of I2 diluted in “inert” (CCl4, n-heptane) solvents and electron donor solvents of increasing complexing strength (CS2, benzene, dioxane, pyridine) have been measured (in the spectral range 400–800 nm) at different times (from 20 ps to 1 ns) after excitation using 25 ps pulses at λ = 532 nm. In inert solvents, the time evolution of the transient spectra are consistent with the model recently proposed by Harris et al.1

Such a behaviour is in marked contrast with the experimental observation in strongly complexing solvents (pyridine). This is interpreted as resulting from a competition between geminate recombination and formation of a complex between the solvent and atomic iodine (I) formed by the photodissociation process. In intermediate complexing solvents these two processes seem to coexist.