The photolysis of SO2 at 3080 Å in the presence of cis- and trans-1,2-difluoroethylene

✍ Scribed by Fred B. Wampler

• Publisher: John Wiley and Sons
• Year: 1976
• Tongue: English
• Weight: 414 KB
• Volume: 8
• Category: Article
• ISSN: 0538-8066
• DOI: 10.1002/kin.550080406

✦ Synopsis

The photolysis of SOz at 3080 A, FWHM = I50 A, and 22°C has been investigated in the presence of cis-and trans-CzFzH2. Quantum yield measurements for the photosensitized isomerization of cis-C2FZH2 to trans-CzFzH2 have been made for a variation in the [SO2]/[czs-C2F2H2] ratio from 0.992 to 253. The results fit a mechanism which is consistent with the S02(3B1) state being the reactive excited state of sulfur dioxide. A mechanism employing only the SOZ(lB1) and SOz(3B1) excited states is quite satisfactory to rationalize the data. A value for the SOz collisionally induced intersystem crossing efficiency from S02('B1) to SOz(3B1) of 0.35 f 0.14 was estimated while the cis-CzFZH2 efficiency was found to be 0.030 f 0.012. The rate constant at 22°C for the removal of SOz(%) molecules by cis-CZF2H2 was found to be (1.43 f 0.13) X 1 0lo l./mole .set. A photostationary composition, [cis]/[trans] = 1.0 =k 0.1, was found from prolonged irradiations of SO, in the presence of the cis and trans isomers.