Stern-Volraer

Stern-Volraer fluorescence quenching constant in nonpolar solvent. 

Investigation of the effect of biacetyl on the decomposition of 2-hexanone in the presence of piperylene provided data for the singlet-state reactivity in type II decomposition It was assumed that product formation from the triplet state was completely quenched in the presence of 0.5 M piperylene, and the decrease caused by added biacetyl was entirely due to quenching of the excited singlet state. The value of the rate coefficient for type II decomposition from the singlet state, obtained from the Stern-Volraer plot, was foxmd to be 10 sec. This indicates that the reactivities of the , -n singlet and triplet states of 2-hexanone in reaction II are of the same order of magnitude. 

From the sensitized phosphorescence of blacetyl, the quantum yield of Inter-system crossing ( ( isc ) was found to be 0.610.1. Prom the slope of the Stern-Volraer plot it can be concluded that the lifetime of the triplet state Is about 30 ns (figure 1). This result is in good agreement with the absence of inhibition by oxygen of dissolved air. The heterolytical scission of the C-Cl bond may be concerted (or not) with the heterolysis of the H-OH bond (18,19). 

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See also in sourсe #XX -- [ , , ]

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