The photophysics and photochemistry of SO2

Heicklen, Julian; Kelly, Nelson A.; Partymiller, Kenneth

doi:10.1007/bf03052425

Cited by 62 publications

(44 citation statements)

References 149 publications

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“…These high 34 S/ 32 S fractionations are consistent with our experimental results (Fig. 4) The photochemistry of SO 2 has been studied extensively and is reviewed elsewhere (e.g., Okabe, 1971;Calvert et al, 1978;Heicklen et al, 1980). Here we focus on the two strong ultraviolet absorption regions of SO 2 , a strong absorption from 165 nm to 240 nm and a weaker absorption from 250 nm to 330 nm (Fig.…”

Section: Results From Cross Section Modelingsupporting

confidence: 92%

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Excitation band dependence of sulfur isotope mass-independent fractionation during photochemistry of sulfur dioxide using broadband light sources

Whitehill

Ono

2012

Geochimica et Cosmochimica Acta

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Section: Results From Cross Section Modelingsupporting

confidence: 92%

“…Photoexcitation in the 250-330 nm absorption region corresponds to the excitation of SO 2 into two singlet excited states (e.g., Heicklen et al, 1980):…”

Section: Results From Cross Section Modelingmentioning

confidence: 99%

Excitation band dependence of sulfur isotope mass-independent fractionation during photochemistry of sulfur dioxide using broadband light sources

Whitehill

Ono

2012

Geochimica et Cosmochimica Acta

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“…Under these conditions, the collision lifetime (on the order of nanoseconds) is considerably shorter than the fluorescence lifetime (on the order of microseconds), allowing rapid collisioninduced rotational and vibrational relaxation of the excited state (20,54). Time-resolved fluorescence experiments performed at 1.33 mbar pure SO 2 showed strong resonance fluorescence from the excited level accompanied by significant fluorescence from vibrationally relaxed molecules (55).…”

Section: Results Of Photochemical Experimentsmentioning

confidence: 99%

Vibronic origin of sulfur mass-independent isotope effect in photoexcitation of SO₂and the implications to the early earth’s atmosphere

Whitehill

Xie

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

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Signatures of mass-independent isotope fractionation (MIF) † Significant deviations from these mass-dependent scaling laws are referred to as mass-independent fractionation (MIF), and serve as important tracers in the earth and planetary sciences (see refs. 3-5).Early studies suggested that MIF could result only from nucleosynthetic processes (6), and the earliest measurements of oxygen MIF in calcium-aluminum inclusions of meteorites originally were interpreted to be nucleosynthetic in origin (7). It eventually was suggested (8) that chemical processes, such as tunneling or processes associated with predissociation, also might produce MIF. The first experimental evidence for a chemical origin of MIF came from ozone generated by an electric discharge or UV radiation (9, 10). The discovery of oxygen MIF in stratospheric ozone (11) soon triggered intense research into the physiochemical origin of MIF in the ozone system (see refs. 12-14). The possible chemical origins of MIF signatures still are poorly understood.For the sulfur isotope system ( 32 S, 33 S, 34 S, and 36 S), Farquhar et al. (15) made the remarkable discovery that mass-independent sulfur isotope fractionation (S-MIF) is prevalent in sedimentary rocks older than ca. 2.4 Ga but absent in rocks from subsequent periods. The disappearance of S-MIF at about 2.4 Ga (16, 17) signifies a fundamental change in the earth's surface sulfur cycles, and generally is linked to the suppression of both SO 2 photolysis and the formation of elemental sulfur aerosols by the rise of atmospheric oxygen levels (15,18,19). The Archean S-MIF is considered the most compelling evidence for an anoxic early atmosphere and constrains Archean oxygen levels to be less than 10−5 of present levels (19). This model of oxygen evolution, however, depends critically on the assumption that UV photolysis of SO 2 by ∼200 nm radiation is the ultimate source of the anomalous sulfur isotope signature (18). Constraining the source of the S-MIF requires a thorough understanding of the physiochemical origins of S-MIF during the photochemistry of SO 2 .SO 2 exhibits two strong absorption band systems in the UV region: one between 185 nm and 235 nm (C 1 B 2 ←X

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“…Ultrafast IC is also responsible for avoiding harmful photochemical reactions of DNA [8,9] and proteins, [10][11][12][13] protecting organisms from UV radiation. IC is also present in the photochemistry of small molecules, for example O 2 and O 3 , [14] SO 2 , [15] NO 2 , [16] and other nitrogen oxides. [17] The absorption of sunlight by these molecules and the subsequent photochemistry are central to atmospheric chemistry and the study of the environment and pollution.…”

Section: Introductionmentioning

confidence: 99%

A general method to describe intersystem crossing dynamics in trajectory surface hopping

Mai

Marquetand

González

2015

Int J of Quantum Chemistry

270

406

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Intersystem crossing is a radiationless process that can take place in a molecule irradiated by UV‐Vis light, thereby playing an important role in many environmental, biological and technological processes. This paper reviews different methods to describe intersystem crossing dynamics, paying attention to semiclassical trajectory theories, which are especially interesting because they can be applied to large systems with many degrees of freedom. In particular, a general trajectory surface hopping methodology recently developed by the authors, which is able to include nonadiabatic and spin‐orbit couplings in excited‐state dynamics simulations, is explained in detail. This method, termed SHARC, can in principle include any arbitrary coupling, what makes it generally applicable to photophysical and photochemical problems, also those including explicit laser fields. A step‐by‐step derivation of the main equations of motion employed in surface hopping based on the fewest‐switches method of Tully, adapted for the inclusion of spin‐orbit interactions, is provided. Special emphasis is put on describing the different possible choices of the electronic bases in which spin‐orbit can be included in surface hopping, highlighting the advantages and inconsistencies of the different approaches. © 2015 Wiley Periodicals, Inc.

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The photophysics and photochemistry of SO2

Cited by 62 publications

References 149 publications

Excitation band dependence of sulfur isotope mass-independent fractionation during photochemistry of sulfur dioxide using broadband light sources

Excitation band dependence of sulfur isotope mass-independent fractionation during photochemistry of sulfur dioxide using broadband light sources

Vibronic origin of sulfur mass-independent isotope effect in photoexcitation of SO₂and the implications to the early earth’s atmosphere

A general method to describe intersystem crossing dynamics in trajectory surface hopping

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The photophysics and photochemistry of SO2

Cited by 62 publications

References 149 publications

Excitation band dependence of sulfur isotope mass-independent fractionation during photochemistry of sulfur dioxide using broadband light sources

Excitation band dependence of sulfur isotope mass-independent fractionation during photochemistry of sulfur dioxide using broadband light sources

Vibronic origin of sulfur mass-independent isotope effect in photoexcitation of SO2and the implications to the early earth’s atmosphere

A general method to describe intersystem crossing dynamics in trajectory surface hopping

Contact Info

Product

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Vibronic origin of sulfur mass-independent isotope effect in photoexcitation of SO₂and the implications to the early earth’s atmosphere