Singlet molecular oxygen results

The chemiluminescence emission at 25-60° C was measured from films of cis-1,4-polybutadiene, 1,2-polybutadiene, and trans-polypentenamer. The polymers were autoxidized previously in air 100°C, or allowed to react with singlet molecular oxygen in solution, and then cast into films. Values of ft (or kaCOz -> 302)/K(102 + polymer -> products)) were determined in benzene for cis-1,4-polybutadiene and cis-1,4-poly-isoprene, and for model compounds cis-3-hexene and cis-3-meihyl-3-hexene by independent methods. The chemiluminescence emission from irradiated films of the polymers containing a dye sensitizer showed a complicated time dependence, and the results depended on the length of irradiation. 

Photochemical transformations of PAH, adsorbed on various substrates are well documented in the literature they may involve radical initiated auto-oxidation, singlet molecular oxygen or hydroxy 1/hydroperoxyl attack. In model systems, several PAH coated on filters or simulant particles have been shown to react fast with ozone or nitrogen dioxide in the dark and to result in the formation of direct mutagens. Any future policy aimed at the reduction of PAH emission levels should therefore also be assessed in terms of possible conversion of PAH into other hazardous products. 

All the quantum dynamics simulations performed show that upon excitation to Si, the P-coordinate dominates the photodynamics, whereas splitting off singlet molecular oxygen (for which the x-coordinate is an important mode) does not play any role. This result is in agreement with the available experiments that found that 2 is obtained after excitation to states higher than Si [82]. 

The CT complex is usually considered as an excited-state complex with radical cation and radical anion character 02 ) [1169, 1170, 1185, 2139]. Such a CT complex formed in liquid monomeric hydrocarbons, ethers and alcohols can result in the formation of singlet molecular oxygen ( A ) [1943,1944]. The available data also suggest that, in certain polar solvents, the CT complex is in equilibrium with the solvated organic radical cation and the superoxide ion (0 2 ). Thus photolysis of the CT band can result in the formation of two independent and reactive forms of molecular oxygen ( Ag and 0 2 ). 

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