Photolysis of SO/sub 2/ at 3130 A in the presence of cis- and trans-2-pentene
The photolysis of SO/sub 2/ at 3130 A, FWHM = 165 A, and 22/sup 0/C has been investigated in the presence of cis- and trans-2-pentene. Quantum yields for the SO/sub 2/ photosensitized isomerization of one isomer to the other have been made for a variation in the (SO/sub 2/)/(C/sub 5/H/sub 10/) ratio of 3.41-366 for cis-2-C/sub 5/H/sub 10/ and of 1.28-367 for trans-2-C/sub 5/H/sub 10/. A kinetic analysis of each of these systems permitted new estimates to be made for the SO/sub 2/ collisionally induced intersystem crossing ratio at 3130 A from SO/sub 2/(/sup 1/B/sub 1/) to SO/sub 2/(/sup 3/B/sub 1/). The estimates of k/sub 1a//(k/sub 1a + k/sub 1b/) obtained are 0.12 +- 0.01 and 0.12 +- 0.02 (two different kinetic analyses in the cis-2-C/sub 5/H/sub 10/ study) and 0.20 +- 0.05 and 0.20 +- 0.04 (two different kinetic analyses in the trans-2-C/sub 5/H/sub 10/ study). Collisionally induced intersystem crossing ratios of k/sub 2a/(k/sub 2a/ + k/sub 2b/) = 0.51 +- 0.10 and k/sub 3a//(k/sub 3a/ + k/sub 3b/) = 0.62 +- 0.12 were obtained for cis- and trans-2-pentene, respectively. Quenching rate constants at 22/sup 0/C for removal of SO/sub 2/(/sup 3/B/sub 1/) molecules by cis- and trans-2-C/sub 5/H/sub 10/ were estimated as (100 +- 0.29) x 10/sup 11/)./mole.sec and (0.857 +- 0.160) x 10/sup 11/)./mole.sec, respectively. Prolonged irradiations, extrapolated to infinite irradiation times, for mixtures initially containing SO/sub 2/ and pure isomer, either the cis or trans, yielded a photostationary composition of (trans-2-pentene)/(cis-2-pentene) = 2.1 +- 0.1.
- Research Organization:
- Los Alamos Scientific Lab., NM
- OSTI ID:
- 7300563
- Journal Information:
- Int. J. Chem. Kinet.; (United States), Vol. 8; Conference: 28. Southeastern Regional ACS meeting, Gatlinburg, TN, USA, 26 Oct 1976
- Country of Publication:
- United States
- Language:
- English
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