Femtosecond pump-probe studies of actinic-wavelength dependence in aqueous chlorine dioxide photochemistry

Journal Article · Tue Apr 21 04:00:00 EDT 2009 · Journal of Chemical Physics

DOI:https://doi.org/10.1063/1.3116108· OSTI ID:21559697

Bixby, Teresa J; Bolinger, Joshua C; Patterson, Joshua D; Reid, Philip J ^[1]

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1. Department of Chemistry, University of Washington, P.O. Box 351700, Seattle, Washington 98195 (United States)

The actinic or photolysis-wavelength dependence of aqueous chlorine dioxide (OClO) photochemistry is investigated using femtosecond pump-probe spectroscopy. Following photoexcitation at 310, 335, and 410 nm the photoinduced evolution in optical density is measured from the UV to the near IR. Analysis of the optical-density evolution illustrates that the quantum yield for atomic chlorine production ({Phi}{sub Cl}) increases with actinic energy, with {Phi}{sub Cl}=0.16{+-}0.02 for 410 nm excitation and increasing to 0.25{+-}0.01 and 0.54{+-}0.10 for 335 and 310 nm excitations, respectively. Consistent with previous studies, the production of Cl occurs through two channels, with one channel corresponding to prompt (<5 ps) Cl formation and the other corresponding to the thermal decomposition of ClOO formed by OClO photoisomerization. The partitioning between Cl production channels is dependent on actinic energy, with prompt Cl production enhanced with an increase in actinic energy. Limited evidence is found for enhanced ClO production with an increase in actinic energy. Stimulated emission and excited-state absorption features associated with OClO populating the optically prepared {sup 2}A{sub 2} surface decrease with an increase in actinic energy suggesting that the excited-state decay dynamics are also actinic energy dependent. The studies presented here provide detailed information on the actinic-wavelength dependence of OClO photochemistry in aqueous solution.

• OSTI ID: 21559697
• Journal Information: Journal of Chemical Physics, Journal Name: Journal of Chemical Physics Journal Issue: 15 Vol. 130; ISSN JCPSA6; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
ABSORPTION
AQUEOUS SOLUTIONS
CHEMICAL REACTIONS
CHEMISTRY
CHLORINE
CHLORINE COMPOUNDS
DECOMPOSITION
DISPERSIONS
ELEMENTS
EMISSION
ENERGY DEPENDENCE
ENERGY-LEVEL TRANSITIONS
EQUIPMENT
EXCITATION
FREQUENCY DEPENDENCE
HALOGEN COMPOUNDS
HALOGENS
HOMOGENEOUS MIXTURES
ISOMERIZATION
KINETICS
MIXTURES
NONMETALS
OPACITY
OPTICAL PROPERTIES
OPTICAL PUMPING
OXYGEN COMPOUNDS
PHOTOCHEMICAL REACTIONS
PHOTOCHEMISTRY
PHOTOLYSIS
PHYSICAL PROPERTIES
PUMPING
PUMPS
PYROLYSIS
REACTION KINETICS
SOLUTIONS
SORPTION
SPECTROSCOPY
STIMULATED EMISSION
SURFACES
THERMOCHEMICAL PROCESSES