CH3OCI: UV/visible absorption cross sections, J values and atmospheric significance

Abstract. The UV-visible absorption spectrum of gaseous IONO2 has been measured over the wavelength range 245--415 nm using the technique of laser photolysis with time-resolved UV-visible absorption spectroscopy. IONO2 was produced in situ in the gas phase by laser flash photolysis of NO2/CF3I/N2 mixtures. Post flash spectra were deconvolved to remove contributions to the observed absorption from other reactant and product species. The resulting spectrum attributed to IONO2 consists of several overlapping broad absorption bands. Assuming a quantum yield of unity for IONO2 photolysis, model calculations show that during sunlit hours at noon, 53° N, the first order solar photolysis rate coefficient (J value) for IONO2 is 4.0 x 10-2 s-1.

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The UV-visible absorption cross-sections of IONO<sub>2</sub>

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-2-765-2002 ◽

2002 ◽

Vol 2 (3) ◽

pp. 765-788 ◽

Cited By ~ 2

Author(s):

J. C. Mössinger ◽

D. M. Rowley ◽

R. A. Cox

Keyword(s):

Cross Sections ◽

Flash Photolysis ◽

Laser Flash Photolysis ◽

Laser Flash ◽

Absorption Bands ◽

Visible Absorption ◽

Time Resolved ◽

Model Calculations ◽

Solar Photolysis ◽

Uv Visible

Abstract. The UV-visible absorption spectrum of gaseous IONO2 has been measured over the wavelength range 245--415 nm using the technique of laser photolysis with time-resolved UV-visible absorption spectroscopy. IONO2 was produced in situ in the gas phase by laser flash photolysis of NO2/CF3I/N2 mixtures. Post-flash spectra were deconvolved to remove contributions to the observed absorption from other reactant and product species. The resulting spectrum attributed to IONO2 consists of several overlapping broad absorption bands. Assuming a quantum yield of unity for IONO2 photolysis, model calculations show that during sunlit hours at noon, 53° N, the first order solar photolysis rate coefficient (J value) for IONO2 is 4.6 x 10-2 s-1.

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New experimental method for determining the S1 → Sn absorption spectrum of highly fluorescent dyes

Canadian Journal of Physics ◽

10.1139/p93-009 ◽

1993 ◽

Vol 71 (1-2) ◽

pp. 59-65 ◽

Cited By ~ 6

Author(s):

Marie-Claire Gazeau ◽

Véronique Wintgens ◽

Pierre Valat ◽

Jean Kossanyi ◽

Denis Doizi ◽

...

Keyword(s):

Excited State ◽

Cross Sections ◽

Fluorescent Dyes ◽

Visible Region ◽

Excited State Absorption ◽

Absorption Cross ◽

Excited Singlet ◽

Uv Visible ◽

The One ◽

State Concentration

A new method has been developed to measure the excited-state absorption cross sections σ1n, of highly fluorescent dyes. which gives excited singlet-state absorption (ESSA) spectra over most of the UV–visible region, including the one where the fluorescence occurs. The error in the σ1n values depends on that for the singlet excited-state concentration. Our method used benzophenone as an actinometer to determine the excited-state concentration. Rhodamine 6G was used to test the method; the ESSA spectrum obtained shows a maximum around 530 nm with an excited-state absorption cross section σ1n value of 2.08 × 10−16 cm2. Our results are discussed and compared with those reported in the literature.

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