Quenching of singlet molecular oxygen by some atmospheric pollutants

Abstract

Room temperature rate constants for the deactivation of singlet molecular oxygen (^(cflAg) by SO2, H2S, CH3SH, CH3COCH3, CH2O, ambient air, and dry synthetic air were measured in a 220-m3 low-pressure reactor under static conditions. Emission at 7620 Á from 02(h12g+), which is continuously produced from the energy pooling reaction 202(1Ag) -Ü2(12g+) + 02(3 ß_), was taken as a relative measure of the 02(1Ag) concentration in the system. The compounds deactivate singlet oxygen at rates comparable to or lower than ground state molecular oxygen. The rate constants for deactivation by CH3SH, dry air, and ambient air are critically compared with literature values. It is concluded that singlet oxygen does not contribute to the atmospheric conversion of the trace gases investigated.

Depth dependence of direct and indirect photolysis on soil surfaces

“…In the vapor phase, the half-life of singlet oxygen can be estimated from the rate constant for deactivation of ^2, 3.4 X 10™19 cm3/molecule-s (Penzhorn et al, 1974).…”

Biochemical effects of excited state molecular oxygen

“…Lastly the importance of singlet O2 generated via atmospheric photochemical processes and the relationship of this oxidant to the biochemistry of atmospheric environments should not be neglected (118,119). Pine pollen has recently been shown (120) to undergo oxidation when exposed to singlet O2 yielding lipid peroxides.…”

Overview on the Development of Chambers for the Study of Atmospheric Chemical Processes

“…Major achievements: New results on the recombination reactions of NO + O + (M) (Becker et al, 1972c;1973), N + N + (M) (Becker et al, 1969;1971a;1972b), reactions of O 2 ( 1 g ) and O 2 ( 1 + g ) with other trace gases (Becker et al, 1971b;1972a;Penzhorn et al, 1974), reactions of O 3 with olefins (Becker et al, 1974a), detection of an energy transfer reaction from O 2 ( 1 g ) to the HO 2 radical and identification of a low lying excited state of HO 2 (Becker et al, 1974b;1975;1978a). The studies on NO + O and N + N included the quantification of radiative recombination by inverse predissociation which could be clearly identified in the low pressure regime.…”