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Title: Kinetic and spectroscopic study of triplet state and ionic pathways in the laser-induced photoexcitation of N-ethylcarbazole in fluid solutions

Abstract

When fluid solutions of N-ethylcarbazole (NEC) are irradiated by 308-nm pulses from an excimer laser, transient triplets and ions may be observed in the microsecond time regime. The formation of ions is favored in more polar solvents such as acetonitrile (AcN) and that of triplets in nonpolar solvents such as paraffin oil. The quantum yield of triplet formation from initial excitation is 0.23. Triplet states decay through concurrent first- and second-order channels: the second-order process, triplet-triplet annihilation, leads to formation of excited singlet states with an efficiency of 0.12. Transient carbazolyl cations and anions display double-exponential decays. To account for this behavior, a mechanism involving initial electron donation by the multiply excited chromophore to a nearby NEC molecule or solvent molecule is proposed; subsequent decay occurs primarily by germinate recombination of the resulting ion pair. The quantum yield for cation production is 0.037. Delayed fluorescence is AcN also decays by a double-exponential decay curve with rate constants, suggesting that the emission arises mainly from ion recombination.

Authors:
;  [1];  [2]
  1. Univ. of Nevada, Reno (United States)
  2. Univ. of Trondheim, Dragvoll (Norway)
Publication Date:
OSTI Identifier:
7273620
DOE Contract Number:  
FG08-84ER45107
Resource Type:
Journal Article
Journal Name:
Journal of Physical Chemistry; (United States)
Additional Journal Information:
Journal Volume: 95:20; Journal ID: ISSN 0022-3654
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; CARBAZOLES; PHOTOCHEMISTRY; ELECTRON TRANSFER; EXPERIMENTAL DATA; IONS; KINETICS; RECOMBINATION; SOLVENTS; AROMATICS; AZAARENES; AZOLES; CHARGED PARTICLES; CHEMISTRY; DATA; HETEROCYCLIC COMPOUNDS; INFORMATION; NUMERICAL DATA; ORGANIC COMPOUNDS; ORGANIC NITROGEN COMPOUNDS; 400500* - Photochemistry

Citation Formats

Haggquist, G W, Burkhart, R D, and Naqvi, K R. Kinetic and spectroscopic study of triplet state and ionic pathways in the laser-induced photoexcitation of N-ethylcarbazole in fluid solutions. United States: N. p., 1991. Web. doi:10.1021/j100173a008.
Haggquist, G W, Burkhart, R D, & Naqvi, K R. Kinetic and spectroscopic study of triplet state and ionic pathways in the laser-induced photoexcitation of N-ethylcarbazole in fluid solutions. United States. https://doi.org/10.1021/j100173a008
Haggquist, G W, Burkhart, R D, and Naqvi, K R. 1991. "Kinetic and spectroscopic study of triplet state and ionic pathways in the laser-induced photoexcitation of N-ethylcarbazole in fluid solutions". United States. https://doi.org/10.1021/j100173a008.
@article{osti_7273620,
title = {Kinetic and spectroscopic study of triplet state and ionic pathways in the laser-induced photoexcitation of N-ethylcarbazole in fluid solutions},
author = {Haggquist, G W and Burkhart, R D and Naqvi, K R},
abstractNote = {When fluid solutions of N-ethylcarbazole (NEC) are irradiated by 308-nm pulses from an excimer laser, transient triplets and ions may be observed in the microsecond time regime. The formation of ions is favored in more polar solvents such as acetonitrile (AcN) and that of triplets in nonpolar solvents such as paraffin oil. The quantum yield of triplet formation from initial excitation is 0.23. Triplet states decay through concurrent first- and second-order channels: the second-order process, triplet-triplet annihilation, leads to formation of excited singlet states with an efficiency of 0.12. Transient carbazolyl cations and anions display double-exponential decays. To account for this behavior, a mechanism involving initial electron donation by the multiply excited chromophore to a nearby NEC molecule or solvent molecule is proposed; subsequent decay occurs primarily by germinate recombination of the resulting ion pair. The quantum yield for cation production is 0.037. Delayed fluorescence is AcN also decays by a double-exponential decay curve with rate constants, suggesting that the emission arises mainly from ion recombination.},
doi = {10.1021/j100173a008},
url = {https://www.osti.gov/biblio/7273620}, journal = {Journal of Physical Chemistry; (United States)},
issn = {0022-3654},
number = ,
volume = 95:20,
place = {United States},
year = {Thu Oct 03 00:00:00 EDT 1991},
month = {Thu Oct 03 00:00:00 EDT 1991}
}