Identification of the photochemically active species in sulfur dioxide photolysis within the first allowed absorption band

Okuda, Sachiko; Rao, T. Navaneeth; Slater, David; Calvert, Jack G.

doi:10.1021/j100846a081

Cited by 39 publications

(16 citation statements)

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“…These previous reports ,− further support our observations that the successive irradiation of the Cl 2 SO/cHex in a static cell led to the generation of S 2 O and SO 3 and suppressed the generation of SO 2 .…”

Section: Results and Discussionsupporting

confidence: 89%

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Does Tetrahydrofuran (THF) Behave like a Solvent or a Reactant in the Photolysis of Thionyl Chloride (Cl₂SO) in Cyclohexane? A Transient Infrared Difference Study

Shih

Chu

2018

J. Phys. Chem. A

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The photolysis of thionyl chloride (ClSO) in pure cyclohexane (cHex) and in cHex with a small amount of tetrahydrofuran (THF) irradiated with 266 nm pulsed laser was investigated using time-resolved step-scan Fourier-transform spectroscopy. The density functional theory B3LYP, with the conductor-like polarizable continuum model to account for the effects of solvents, was employed to predict the molecular parameters of the relevant species. Monitoring the wavenumbers and infrared absorbances attributed to the [S,O] species and accounting for the stoichiometry revealed SO to be the major oxygen-containing end product for the thermal decomposition of ClSO. Upon successive irradiation with 266 nm pulsed laser, the major product, as detected by IR absorption, was SO with minor SO, which could be generated from the secondary reactions of the photolytic intermediate ClSO. The majority of the transient vibrational features upon 266 nm irradiation of the mixture of ClSO/cHex was attributed to ClSO, characterized at 1155 cm, coupled with a minor contribution of (ClSO) at 1212 and 1173 cm. For the mixture of ClSO/THF/cHex, the transient population of ClSO was retained, but the amount of (ClSO) was slightly reduced, coupled with a new upward feature at 1054 cm that was plausibly attributed to the C-O-C asymmetric stretching mode of ClSO-THF complex. Upon the successive irradiation of the ClSO/THF/cHex mixture, the amount of SO was also decreased. The observed complexes of THF with solutes suggested that THF should not be merely treated as a solvent but regarded as a coordination molecule in organic synthesis. The formation of the intermediate-THF complexes altered the reaction pathways, as well as the types and populations of the end products.

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Section: Results and Discussionsupporting

confidence: 89%

“…At excitation wavelengths greater than 218 nm, the photodissociation of SO 2 is not energetically allowed, although SO 2 can be excited by 266 nm photons (σ = 4 × 10 –19 cm 2 ) . The light-induced electronically excited SO 2 , denoted as SO 2 *, can react with another SO 2 to generate SO 3 and SO, .…”

Section: Results and Discussionmentioning

confidence: 99%

Does Tetrahydrofuran (THF) Behave like a Solvent or a Reactant in the Photolysis of Thionyl Chloride (Cl₂SO) in Cyclohexane? A Transient Infrared Difference Study

Shih

Chu

2018

J. Phys. Chem. A

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“…The triplet state has a phosphorescence lifetime of ∼0.9 ms and is proposed to be involved in several interesting atmospheric reactions. ,,− ,− The 3 SO 2 molecule is known to react with carbon monoxide (CO) and with ground state SO 2 . ,, …”

Section: Resultsmentioning

confidence: 99%

“…,77,84−87,92−95 The 3 SO 2 molecule is known to react with carbon monoxide (CO) and with ground state SO 2 92,96,97. …”

mentioning

confidence: 99%

Spectroscopy of OSSO and Other Sulfur Compounds Thought to be Present in the Venus Atmosphere

et al. 2020

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The spectroscopy of cis-OSSO and trans-OSSO is explored and put into the context of the Venusian atmosphere, along with other sulfur compounds potentially present there, namely, S 2 O, C 1-S 2 O 2 , trigonal-S 2 O 2 , and S 3. UV−vis spectra were calculated using the nuclear ensemble approach. The calculated OSSO spectra are shown to match well with the 320−400 nm near-UV absorption previously measured on Venus, and we discuss the challenges of assigning OSSO as the Venusian near-UV absorber. The largest source of uncertainty is getting accurate concentrations of sulfur monoxide (3 SO) in the upper cloud layer of Venus (60−70 km altitude) since the 3 SO self-reaction is what causes cis-and trans-OSSO to form. Additionally, we employed the matrix-isolation technique to trap OSSO formed by microwave discharging a gas mixture of argon and SO 2 and then depositing the mixture onto a cold window (6−12 K). Anharmonic vibrational transition frequencies and intensities were calculated at the coupled cluster level to corroborate the matrix-isolation FTIR spectra. The computationally calculated UV−vis and experimentally recorded IR spectra presented in this work aid future attempts at detecting these sulfur compounds in the Venusian atmosphere.

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“…Photo-oxidation processes were considered, − namely disproportionation and spin-forbidden reaction with O 2 , ,− but experiments showed that upon exposure to sunlight, SO 2 in air is oxidized to SO 3 only in the presence of pollutants . Reaction with hydrocarbons RH was shown to produce R and HOSO radicals through H-transfer. , There is now consensus that the reactive entity in the photochemistry of pure sulfur dioxide is the triplet state molecule 3 SO 2 . , The lowest triplet state ( 3 B 1 ) can be reached by direct absorption of light or by intersystem crossing from the lowest excited singlet states ( l A 2 and 1 B 1 ) in the first allowed absorption band, which extends from 240 to 330 nm, and the excited states decay into the ground state through radiative or nonradiative processes (eqs –). The lifetime of the lowest triplet state of SO 2 has been estimated to τ = (7.9 ± 1.7) 10 –4 s …”

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confidence: 99%

Photochemistry of SO₂ at the Air–Water Interface: A Source of OH and HOSO Radicals

et al. 2018

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The photochemistry of sulfur dioxide in the near UV-vis energy range has been studied in aqueous environments. The combination of previously reported experimental measurements with accurate quantum chemical calculations achieved in this work reveals that the process represents an important source of OH radicals in the troposphere. It implicates the reaction of the lowest triplet excited state of SO with a water molecule. When the process occurs in the gas-phase, photochemical OH production is only significant under high humidity conditions and high SO concentrations as those measured in polluted urban areas. However, the OH production rate increases by several orders of magnitude when the process takes place at the surface of water droplets. The present study indicates therefore that the atmospheric importance of sulfur dioxide goes beyond its well-known role as acid rain and aerosol formation precursor.

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Identification of the photochemically active species in sulfur dioxide photolysis within the first allowed absorption band

Cited by 39 publications

References 0 publications

Does Tetrahydrofuran (THF) Behave like a Solvent or a Reactant in the Photolysis of Thionyl Chloride (Cl₂SO) in Cyclohexane? A Transient Infrared Difference Study

Does Tetrahydrofuran (THF) Behave like a Solvent or a Reactant in the Photolysis of Thionyl Chloride (Cl₂SO) in Cyclohexane? A Transient Infrared Difference Study

Spectroscopy of OSSO and Other Sulfur Compounds Thought to be Present in the Venus Atmosphere

Photochemistry of SO₂ at the Air–Water Interface: A Source of OH and HOSO Radicals

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Identification of the photochemically active species in sulfur dioxide photolysis within the first allowed absorption band

Cited by 39 publications

References 0 publications

Does Tetrahydrofuran (THF) Behave like a Solvent or a Reactant in the Photolysis of Thionyl Chloride (Cl2SO) in Cyclohexane? A Transient Infrared Difference Study

Does Tetrahydrofuran (THF) Behave like a Solvent or a Reactant in the Photolysis of Thionyl Chloride (Cl2SO) in Cyclohexane? A Transient Infrared Difference Study

Spectroscopy of OSSO and Other Sulfur Compounds Thought to be Present in the Venus Atmosphere

Photochemistry of SO2 at the Air–Water Interface: A Source of OH and HOSO Radicals

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Does Tetrahydrofuran (THF) Behave like a Solvent or a Reactant in the Photolysis of Thionyl Chloride (Cl₂SO) in Cyclohexane? A Transient Infrared Difference Study

Does Tetrahydrofuran (THF) Behave like a Solvent or a Reactant in the Photolysis of Thionyl Chloride (Cl₂SO) in Cyclohexane? A Transient Infrared Difference Study

Photochemistry of SO₂ at the Air–Water Interface: A Source of OH and HOSO Radicals