FORMATION OF EXCITED SINGLET SPECIES IN MERCURY 6(3P1) PHOTOSENSITIZED DECOMPOSITION OF CYCLOBUTANONE

The photosensitized decomposition of cyclobutanone is used to evaluate the contribution of excited singlet species following Hg 6(3P1 photosensitization; 10.5% of the products arise from a singlet pathway. The pressure dependences of the intramolecular hydrocarbon products ethylene, cyclopropane, and propylene have been determined over the range 0.3-20 Torr. Stern-Volmer plots of quenching vs. cyclopentene show that the products arise almost exclusively from the mercury-sensitized pathway. An estimate of about 105 ± 2 kcal/mole is made for the average energy transferred to the cyclobutanone molecule from the excited mercury atom. The results are compared to those obtained from the mercury-photosensitized decomposition of ketene, for which an appreciable singlet contribution (13 ± 2%) has also been reported. © 1969, American Chemical Society. All rights reserved.